      Notice: This opinion is subject to correction before publication in the PACIFIC REPORTER.
      Readers are requested to bring errors to the attention of the Clerk of the Appellate Courts,
      303 K Street, Anchorage, Alaska 99501, phone (907) 264-0608, fax (907) 264-0878, email
      corrections@akcourts.us.



               THE SUPREME COURT OF THE STATE OF ALASKA

DARCEY GELDERMANN,                             )
                                               )        Supreme Court Nos. S-16381/16401
                      Appellant and            )
                      Cross-Appellee,          )        Superior Court No. 3AN-10-12834 CI
                                               )
              v.                               )        OPINION
                                               )
MATTHEW GELDERMANN,                            )        No. 7281 – August 31, 2018
                                               )
                      Appellee and             )
                      Cross-Appellant.         )
                                               )

              Appeal from the Superior Court of the State of Alaska, Third
              Judicial District, Anchorage, Patrick J. McKay, Judge.

              Appearances: Allison Mendel and John J. Sherman, Mendel
              Colbert & Associates, Inc., Anchorage, for Appellant and
              Cross-Appellee. Rhonda F. Butterfield, Wyatt & Butterfield,
              LLC, Anchorage, for Appellee and Cross-Appellant.

              Before: Stowers, Chief Justice, Winfree, Maassen, Bolger,
              and Carney, Justices.

              MAASSEN, Justice.

I.    INTRODUCTION
              The parents of a young son divorced in 2011, agreeing that the mother
would have primary physical custody during the school year. The father moved to
California. When the child began experiencing behavioral problems, the parents agreed
to switch custody for a few years, giving the father primary physical custody in
California during the school year. The parties signed a custody modification agreement
to this effect in December 2014, including both parents’ waivers of child support, but
they did not file the agreement in court.
             The next year, following a dispute over the mother’s visitation, both parties
sought a judicial resolution of custody. The father went to a California court seeking to
make the 2014 change in custody permanent. The mother went to Alaska superior court
seeking to enforce the original 2011 agreement that gave her primary physical custody.
The Alaska court asserted jurisdiction; it ultimately modified physical custody in favor
of the father but maintained the parents’ joint legal custody. The court also modified
child support, ordering the mother to pay child support effective from the date the father
first sought to modify custody in California.
             The mother appeals the physical custody and child support orders,
challenging among other things the child support order’s effective date. The father
cross-appeals, challenging the decision on joint legal custody. We affirm the court’s
custody and child support orders, concluding that they are well supported by the
evidence and that the court did not abuse its discretion in selecting the child support
order’s effective date.
II.   FACTS AND PROCEEDINGS
      A.     Facts
             Darcey and Matthew Geldermann married in 2005 and had a son in 2008.
They divorced in February 2011. The superior court approved a custody agreement that
established joint legal custody but gave primary physical custody to Darcey, with
Matthew receiving visitation during summers and holidays. Matthew thereafter moved
to Washington, spent time as a contractor in Iraq, and eventually settled in California.




                                            -2-                                     7281

             1.     Custody experiment
             The parties agree that their son exhibited behavioral problems when he
started kindergarten in 2013; psychologists diagnosed him with autism, atypical attention
deficit and hyperactivity disorder, unspecified anxiety disorder, and social
communication disorder. To deal with these problems Darcey and Matthew agreed to
try a temporary custody switch: their son would live primarily with Matthew in
California for two and a half years and visit Darcey over summers and holidays. Around
December 2014, when the child was six, the parties negotiated a new custody agreement
that acknowledged the switch, but they did not formalize their new agreement in court.
             The informal new arrangement worked well for about 10 months. The child
started school in California in January 2015. Matthew hired a nanny and established a
rigorous routine, including many extracurricular activities. The child had fewer
behavioral problems, and his grades improved. Matthew claims that his son “thrived”
under the new arrangement.
             But the arrangement broke down in the fall of 2015 after a dispute over a
planned visit by Darcey. The superior court found that the dispute generated “some
angry emails,” including threats by Darcey that she would retrieve the child from
California and make it difficult for Matthew to see him again. The parties filed custody-
related motions in both California and Alaska courts; meanwhile the child remained with
Matthew in California.
             While both cases were pending, the parties struggled to maintain civil
communication with each other. The California court awarded Darcey a visit with her
son in November 2015 when she was there for a hearing; the visit was not a success,
though the parties disagree on why. In March 2016 Matthew moved the child to a new
school following a bullying incident and failed to immediately inform Darcey of the
change. In April the Alaska superior court, retaining jurisdiction, awarded Darcey

                                           -3-                                     7281

spring-break visitation, requiring only that she provide an itinerary. The parties
disagreed about how specific the itinerary needed to be, and Darcey ultimately canceled
her visit. The superior court described the “failure” of the spring break visit as
“disturbing” and “highly unfortunate.”
             2.     Child support
             As part of their 2011 divorce, the parties’ court-approved settlement
agreement provided that Matthew would pay Darcey child support. But when their son
moved in with Matthew in December 2014, “[t]he parties agree[d] that neither party
[would] owe child support to the other party as a result.” In January 2015, accordingly,
Darcey withdrew from the collection services provided by Alaska’s Child Support
Services Division (CSSD). But when their current dispute arose, Darcey again requested
CSSD assistance, and Matthew received a letter from CSSD in October 2015 directing
that he pay Darcey the child support required by the 2011 agreement.
      B.     Proceedings
             1.     Custody
             In early October 2015 Matthew filed an ex parte custody action in
California, seeking a transfer of jurisdiction from Alaska, a temporary emergency
custody order, and a modification of custody to reflect the parties’ 2014 agreement
giving him primary physical custody. Shortly thereafter Darcey commenced the current
Alaska proceedings; she filed a motion to enforce the original 2011 custody arrangement
that gave her primary physical custody. The Alaska superior court conferred with the
California court, held an evidentiary hearing on jurisdiction in January 2016, concluded
that neither forum was convenient for both parties, and ultimately decided to retain
jurisdiction in Alaska.
             Matthew had not filed a motion in Alaska to modify custody. The superior
court concluded, however, that his opposition to Darcey’s motion to enforce the 2011

                                          -4-                                      7281

order amounted to, “at the very least, an implied custody modification request,” and it
scheduled a trial on both physical and legal custody. The parties presented a number of
witnesses, including themselves, their respective new spouses, their son’s California
nanny, and Darcey’s mother.
             After hearing the evidence, the court denied Darcey’s motion to enforce the
2011 order and awarded Matthew primary physical custody during the school year.
Darcey was given summer vacations and alternating holidays as well as “generous and
liberal, unrestricted, unsupervised visits with [the child], whenever she is in the same
geographic location.” Although the court found significant communication problems
between Darcey and Matthew, it continued joint legal custody.           Darcey sought
reconsideration, claiming that custody modification was inappropriate absent a formal
motion from Matthew. The court denied the motion, explaining that custody and
visitation had been “always clearly at issue.”
             2.     Child support
             In October 2015 Darcey filed a motion to reduce to judgment past-due
amounts of child support calculated under the 2011 order. In early December Matthew
sought to stay enforcement of those child support provisions, and in January 2016 the
court issued an order precluding collection of child support arrears from December 2014
until it ordered otherwise.
             Matthew did not file any other documents related to child support until
May 18, 2016, following the court’s custody decision, when he filed a proposed child
support order. He proposed an effective date of “November 1, 2015, which is the first
of the month after [Darcey] was formally served with notice of [Matthew’s] custody
action in California.” Darcey objected, arguing that Alaska Civil Rule 90.3(h)(2)
prohibited a retroactive date because Matthew had never filed a motion to modify child
support.

                                          -5-                                     7281

              The court signed a new child support order on June 1, 2016, requiring
Darcey to pay support to Matthew. The order used Matthew’s proposed effective date
of November 1, 2015. Darcey sought reconsideration, which was denied.
              Both parties appealed. Darcey seeks review of the physical custody and
child support orders, and Matthew challenges the award of joint legal custody.
III.   STANDARDS OF REVIEW
              “Superior courts have broad discretion in child custody decisions, and we
will reverse only if findings of fact are clearly erroneous or if the superior court abused
its discretion.”1 “A factual finding is clearly erroneous when a review of the record
leaves [us] with a definite and firm conviction that the superior court has made a
mistake.”2 “An abuse of discretion exists where the superior court ‘considered improper
factors in making its custody determination, failed to consider statutorily mandated
factors, or assigned disproportionate weight to particular factors while ignoring
others.’ ”3 “Additionally, an abuse of discretion exists if the superior court’s decision
denied a substantial right to or substantially prejudiced a party.”4
              “We review an award of child support for abuse of discretion.”5 But
“[w]hether the superior court applied the correct legal standard to its child support



       1
             Riggs v. Coonradt, 335 P.3d 1103, 1106 (Alaska 2014) (citing Ronny M.
v. Nanette H., 303 P.3d 392, 399 (Alaska 2013)).
       2
              Id. (quoting Ronny M., 303 P.3d at 399).
       3
              Id. (quoting Ronny M., 303 P.3d at 399).
       4
            Ronny M., 303 P.3d at 400 (citing House v. House, 779 P.2d 1204, 1206
(Alaska 1989)).
       5
            Limeres v. Limeres, 320 P.3d 291, 295 (Alaska 2014) (citing Swaney v.
Granger, 297 P.3d 132, 136 (Alaska 2013)).
                                           -6-                                       7281

determination is a question of law that we review de novo.”6 Finally, “[t]he adequacy
of the notice and hearing afforded a litigant in child custody proceedings involves due
process considerations,” which we also review de novo.7
IV.	   DISCUSSION
       A.	    The Superior Court Did Not Abuse Its Discretion By Finding A
              Substantial Change In Circumstances For Purposes Of Modifying
              Physical Custody.
              “Alaska Statute 25.20.110 authorizes courts to modify child-custody and
visitation awards if (1) there has been a change in circumstances that justifies
modification and (2) the modification is in the best interests of the child.”8 “Once the
movant meets [the initial] burden [of changed circumstances], he or she is entitled ‘to a
hearing to consider whether, in light of such changed circumstances, it is in the child’s
best interests to alter the existing custodial arrangement.’ ”9
              Darcey challenges only the court’s decision on the first element of the
modification test: that there was a change in circumstances substantial enough to justify
a modification of custody. We have held that “[a] change in circumstances is unlikely
to be substantial enough to ‘overcome our deep reluctance to shuttle children back and
forth between parents’ unless the change affects the children’s welfare and ‘reflect[s]




       6
              Id. (citing Koller v. Reft, 71 P.3d 800, 804 (Alaska 2003)).
       7
              Lashbrook v. Lashbrook, 957 P.2d 326, 328 (Alaska 1998).
       8
            Rego v. Rego, 259 P.3d 447, 452 (Alaska 2011) (citing Melendrez v.
Melendrez, 143 P.3d 957, 962 (Alaska 2006)).
       9
            Lashbrook, 957 P.2d at 329 (quoting A.H. v. W.P., 896 P.2d 240, 244
(Alaska 1995)).
                                            -7-	                                   7281

more than mere passage of time.’ ”10 Whether changed circumstances justify
modification “is heavily fact-intensive” and “appropriately gauged by its effect on the
child.”11 “The change in circumstances ‘must be demonstrated relative to the facts and
circumstances that existed at the time of the prior custody order that the party seeks to
modify.’ ”12
               The superior court in this case had to decide whether circumstances had
substantially changed since the first custody agreement in 2011.13 In deciding that they
had, the court relied on the change that prompted Darcey and Matthew to shift custody
in 2014: “[T]here ha[s] been a change in circumstances . . . that was recognized by the
parties when they agreed that [the child] would reside, at least temporarily, with his
father.” It is undisputed that the child had behavioral problems in Alaska, and both
parties agreed it would benefit him to live with Matthew in California for several years.
Matthew had also had a change in employment that allowed for a more permanent
residence, and both parents had remarried. The superior court did not abuse its discretion




      10
              Collier v. Harris, 377 P.3d 15, 22 (Alaska 2016) (second alteration in
original) (quoting Hope P. v. Flynn G., 355 P.3d 559, 565 (Alaska 2015)).
      11
               Id. at 22, 23 n.31.
      12
            Nelson v. Nelson, 263 P.3d 49, 52 (Alaska 2011) (quoting Peterson v.
Swarthout, 214 P.3d 332, 341 (Alaska 2009)).
      13
               The 2014 agreement was not filed with the Alaska court until the current
litigation, so our baseline for assessing change is the court-approved 2011 parenting
agreement. See McClain v. McClain, 716 P.2d 381, 385 (Alaska 1986) (“Trial courts,
not parents, are the ultimate decision makers as to custody and are not bound by private
agreements.”).
                                           -8-                                      7281

in concluding that these new circumstances, in combination, amounted to a substantial
change.14
             Citing McLane v. Paul,15 Darcey argues that, as a matter of law, her
temporary agreement with Matthew should not qualify as a substantial change in
circumstances because “parties should be allowed to experiment with new custodial
arrangements without the fear that they will automatically become permanent.” But the
superior court did not point to the “new custodial arrangement” as the substantial change;
rather, the court relied on the underlying circumstances that prompted the new custodial
arrangement. The fact that the parties themselves recognize the substantiality of a
change in circumstances and agree tentatively on how to deal with it cannot foreclose the
court from recognizing the same thing.
      B.	    The Superior Court Did Not Violate Darcey’s Due Process Rights By
             Considering A Modification of Custody Without A Formal Motion
             From Either Party.
             Darcey argues that Matthew’s failure to file a motion to modify custody in
Alaska prevented her from understanding “what the alleged change in circumstances
was,” thus violating her due process rights to notice and a hearing. “Procedural due
process under the Alaska Constitution requires ‘notice and opportunity for hearing


      14
             See Heather W. v. Rudy R., 274 P.3d 478, 482 (Alaska 2012) (“When
reviewing whether a trial court was justified in finding a change in circumstances, we do
not parse each alleged factual assertion of change, but instead look to see whether the
circumstances in the aggregate establish a change of circumstances.”); Hunter v.
Conwell, 219 P.3d 191, 197 (Alaska 2009) (“[T]he allegation that the boys have
exhibited significant anger and behavioral issues after returning from Conwell’s
home[, among other things], could warrant modification of custody.”).
      15
              189 P.3d 1039, 1044-45 (Alaska 2008) (holding that temporary agreement
to allow child to stay with her father for one school year did not qualify as substantial
change).
                                           -9-	                                     7281

appropriate to the nature of the case.’ ”16 “To comply with due process, notice must be
given sufficiently in advance of scheduled court proceedings so that the parties have a
reasonable opportunity to prepare.”17 We have explained that “[i]t is essential to
contested custody proceedings that the parties be afforded a hearing which grants them
the opportunity to present the quantum of evidence needed to make an informed and
principled determination.”18 But we have held that even without a formal motion from
either party, “the trial court may decide [custody] issues on its own motion, as long as
a party has raised them and both sides have the opportunity to present full testimony.”19
              Darcey argues that in the absence of a formal motion to modify custody, she
“lacked notice as to the disputed issues and therefore had no ability to prepare to respond
to Matthew’s case.” Darcey acknowledges that she received “late notice” at the trial call
that modification was at issue, but she argues that because she was unrepresented, the
absence of a formal motion “deprived her of any understanding of the issues to be
addressed at trial, or the case Matthew intended to present against her retaining custody.”
              We have found due process violations in several cases when a parent lacked
notice that permanent custody was at issue or the hearing was insufficient to determine



       16
             Lashbrook v. Lashbrook, 957 P.2d 326, 328 (Alaska 1998) (quoting Wright
v. Black, 856 P.2d 477, 480 (Alaska 1993)).
       17
             Childs v. Childs, 310 P.3d 955, 960 (Alaska 2013) (citing Fidler v. Fidler,
296 P.3d 11, 13 n.5 (Alaska 2013)).
       18
            Lashbrook, 957 P.2d at 328 (quoting Cushing v. Painter, 666 P.2d 1044,
1046 (Alaska 1983)).
       19
             T.M.C. v. S.A.C., 858 P.2d 315, 318-19 (Alaska 1993). Because “the two
prongs of the [custody modification] test are sufficiently interwoven,” the court has
authority “to act on [its] own motion” regarding either a substantial change in
circumstances or the subsequent best interests determination. Id. at 319.
                                           -10-                                      7281

the child’s best interests.20 In Siekawitch v. Siekawitch, on the other hand, we rejected
a father’s due process claim because of his actual “notice that [the mother] sought equal
time with the children.”21 Although the mother had not filed a motion to modify physical
custody, she had sought equal time through a change in visitation “in her memorandum
in support of her motion for a specific custody schedule, in her reply to [the father’s]
opposition to the motion, and in her proposed visitation order.”22 Because the father’s
pretrial motions and his conduct at trial indicated that he “was aware of [the mother’s]
intentions” to seek equal time, we concluded that the father had sufficient notice of a
possible modification to satisfy due process.23
             Darcey’s case is not meaningfully distinguishable from Siekawitch. First,
Matthew’s filings and the court’s comments clearly indicated that custody modification

      20
              Debra P. v. Laurence S., 309 P.3d 1258, 1261 (Alaska 2013) (finding due
process violation where superior court based its custody decision on “hearing [that]
would decide issues of interim custody” and had told parties “that another final hearing
[on permanent custody] would be scheduled if the parties were unable to reach a
settlement”); Potter v. Potter, 55 P.3d 726, 728-29 (Alaska 2002) (holding due process
was violated where father “was given no notice that modification of decreed visitation
was at issue — indeed, based on the court’s rulings, both parties reasonably expected that
decreed visitation would not be at issue”); Lashbrook, 957 P.2d at 329-30 (remanding
custody determination where trial court relied on previous domestic violence hearing in
determining custody rather than holding hearing to address the “eight other factors
specified in AS 25.24.150(c)”); Cushing, 666 P.2d at 1046 (finding due process violation
where mother only received five days notice and “because of the time constraints
imposed, the parties were limited to four witnesses apiece”).
      21
             956 P.2d 447, 450 (Alaska 1998).
      22
             Id.
      23
              Id.; see also Easley v. Easley, 394 P.3d 517, 521 (Alaska 2017) (“Because
of the previous back-and-forth between the parties on the issue of enforcement of the
divorce decree, [the former husband] lacked neither notice of [the former wife’s] desire
to be paid her share of the estate nor an opportunity to oppose her arguments.”).
                                          -11-                                      7281

was at issue.24 Although Matthew did not file a motion to modify custody in Alaska, he
did file one in California, served on Darcey on October 8, 2015. And Matthew’s motion
to transfer jurisdiction, filed two weeks later in Alaska, clearly conveyed his intent to
modify custody in whichever state took jurisdiction. His January 14, 2016 reply on the
jurisdiction issue also discussed which state should “hear the custody modification
action.”
              The superior court’s interactions with Darcey clearly indicated its intent to
consider modifying custody. When the court decided to retain jurisdiction in January
2015, it stated that modification would be the subject of a future evidentiary hearing and
asked the parties when they would be ready for it. At trial call, 15 days before the
evidentiary hearing, the court clearly stated that physical and legal custody were at
issue.25 And at the beginning of the hearing the court again stated that the “hearing [was]
on custody modification.”
              Finally, the record supports a conclusion that Darcey understood from the
outset that Matthew was seeking to modify custody.26 She acknowledged that she knew
Matthew was attempting to modify custody in California when she sought the protection
of Alaska’s courts: “Matthew . . . is trying to modify custody in California. He filed our
Alaska custody order in the court of Orange County and is trying to modify it through

       24
              See Siekawitch, 956 P.2d at 450.
       25
               Darcey pointed out that Matthew had not filed a motion to modify custody,
and the superior court noted that “there’s an opposition to your motion to enforce which
is at the very least an implied custody modification.” There is no written opposition to
Darcey’s motion to enforce the 2011 custody order, as Matthew concedes. But his other
filings clearly indicated his opposing position.
       26
             See Siekawitch, 956 P.2d at 450 (“[T]he record discloses that [the father]
was aware of [the mother’s] intentions; in his opposition to [the mother’s] motion, he
expressly acknowledged that [she] sought to share physical custody equally with him.”).
                                           -12-                                      7281

the State of California and not Alaska.” When the court advised her at the trial call to
“be prepared for the court to rule on who should have physical and legal custody,
okay?,” Darcey responded “Okay.” Her trial brief, filed the day before trial, addressed
“Custody Modification/Enforcement,” argued that “[t]here should be no modification of
custody granted, and only enforcement of the existing order,” and addressed the statutory
best interests factors. We conclude that the superior court did not err in concluding that
Darcey had sufficient notice of a possible custody modification.27
              Darcey also had a sufficient opportunity to be heard; the hearing enabled
the superior court to make a principled custody decision.28 Both parties presented
evidence on the best interests factors. Darcey’s witnesses addressed her ability to care
for the child and contrasted it with Matthew’s. She cross-examined Matthew about their
relative abilities to foster their son’s relationship with the other parent, Matthew’s home
environment, and his relationship with his family. She does not point to any additional
evidence she would have presented if she had received earlier or more specific notice.



       27
              See id.; see also Childs v. Childs, 310 P.3d 955, 961 (Alaska 2013) (holding
due process was not violated in a child support proceeding where father received notice
in October, “had an opportunity to make his legal arguments and submit relevant
financial documents,” and the superior court did not issue final custody order until the
following February); Rebecca L. v. Martin C., No. S-14509, 2013 WL 1092714, at *3-4
(Alaska Mar. 13, 2013) (concluding that eight days’ notice satisfied due process where
“the parties had agreed years earlier” that they would revisit custody around that time,
“they had been negotiating a custody modification for over a year by the time of the
hearing,” mother had notice permanent custody was at issue, parents and court wanted
resolution before school started in the fall, and mother “was able to present sufficient
evidence allowing the superior court to make a determination and the record does not
reflect minimal preparation”).
       28
            See Lashbrook v. Lashbrook, 957 P.2d 326, 328 (Alaska 1998) (quoting
Cushing v. Painter, 666 P.2d 1044, 1046 (Alaska 1983)).
                                           -13-                                      7281

Even taking Darcey’s self-represented status into account, we conclude that her due
process rights were not violated.29
      C.	    It Was Not Error To Select November 1, 2015, As The Effective Date
             Of The Modified Child Support Award.
             We have observed that “a significant modification of the physical custody
schedule is likely to require a new child support determination, regardless of whether a
parent requests it.”30 But whether a parent requested the modification is relevant to
whether the new order can have anything but prospective effect. Although Alaska Civil
Rule 90.3(h)(2) prohibits most retroactive modifications of “[c]hild support arrearage,”
the rule further provides that a modification may be made effective “on or after the date
that a motion for modification . . . is served on the opposing party.”31 Darcey points out


      29
              Darcey relies heavily on VinZant v. Elam, in which we concluded that a
show-cause hearing on a motion to enforce custody was insufficient under due process
to allow a modification of custody. 977 P.2d 84, 86-87 (Alaska 1999). But unlike in
VinZant, the parties here had notice and an opportunity to address the best interests
factors. See id. at 87.
      30
               Wells v. Barile, 358 P.3d 583, 589 (Alaska 2015) (observing that court’s
entry of a tentative child support order reflecting ordered change in custody “was plainly
the proper course” even though party moving for modification of custody had not
requested change in support); see Swaney v. Granger, 297 P.3d 132, 137 n.15 (Alaska
2013) (“We note that under Rule 90.3(a) the change of a child’s primary physical
custodian from one parent to the other ordinarily will require modification of an existing
support order.”); Potter v. Potter, 55 P.3d 726, 729 (Alaska 2002) (“Ordinarily, when
parties informally agree to make a change in decreed custody or visitation that is not
merely temporary or experimental, the change should be reflected both in a changed
custody or visitation order and in a changed child support order.”).
      31
             The full text of Rule 90.3(h)(2) is as follows:
             No Retroactive Modification. Child support arrearage may
             not be modified retroactively, except as allowed by
                                                                     (continued...)
                                          -14-	                                     7281

that Matthew never filed a motion to modify child support, and she argues that the
superior court violated the retroactivity bar when it modified child support effective
November 1, 2015, the first day of the month after Matthew filed his motion for
modification of custody in California.
              In light of the purposes of Rule 90.3(h)(2) and the realities of custody
litigation, we reject Darcey’s argument. We conclude that when, as here, a parent moves
to modify custody based on an existing, de facto custody change, the prohibition on
retroactivity does not bar the superior court from making a corresponding change in child
support effective from the date the modification motion is served on the opposing party.
              A baseline principle is that child support calculations “must be based on the
custody actually ordered, not exercised.”32 We explained in Turinsky v. Long that “[i]f
the parties do not follow the custody order, they should ask the court to enforce the
custody order or should move to modify the child support order.”33 Although modified
child support may be calculated from the date a motion to modify child support is served
on the opposing party, “[w]e have read Rule 90.3(h)(2) to prohibit increases or decreases
in child support effective before” that date.34 Superior courts have discretion to choose
a later date, but “the motion service date” is the earliest available date and “should be the

       31
              (...continued)
              AS 25.27.166(d) [where paternity is disestablished]. A
              modification which is effective on or after the date that a
              motion for modification, or a notice of petition for
              modification by the Child Support Services Division, is
              served on the opposing party is not considered a retroactive
              modification.
       32
              Turinsky v. Long, 910 P.2d 590, 598 (Alaska 1996).
       33
              Id. at 595.
       34
              Boone v. Boone, 960 P.2d 579, 585 (Alaska 1998).
                                            -15-                                       7281

preferred effective date.”35 “[T]he superior court should exercise its discretion in
selecting a different effective date only if it finds good cause for doing so.”36
              We recognize that our case law has not been entirely consistent on the issue
of what “motion for modification” can be used to satisfy Rule 90.3(h)(2). We have not
allowed the “functional equivalent” of a modification motion to determine the effective
date of a support order.37 In Millette v. Millette we held that the earliest date the court
could use for a modification of child support was the date the father received notice of
the mother’s motion for modification of child support, which was months after the
superior court had ordered a temporary change in custody; we noted that neither the
court’s custody order nor the mother’s motion seeking modification of custody
mentioned child support.38 We explained that a formal motion to modify child support
was required “even where the circumstances have materially changed and a modification


       35
              Id.
       36
              Id.
       37
              See Millette v. Millette, 177 P.3d 258, 266 (Alaska 2008) (“We have held
that ‘[w]ithout a valid motion before the court, a modification of child support would be
retroactive and thus prohibited.’ This is true even where the circumstances have
materially changed and a modification would likely be permitted upon motion.”
(footnote omitted) (alteration in original) (quoting Wright v. Wright, 22 P.3d 875, 879
(Alaska 2001))); Wright, 22 P.3d at 879 (“The only documents that satisfy the
requirements of Rule 90.3 are motions or petitions for modification.”); State, Dep’t of
Revenue, Child Support Enf’t Div., ex rel. Husa v. Schofield, 993 P.2d 405, 409 (Alaska
1999) (“[W]e specifically rejected the idea that documents not mentioned in the text of
the rule can be the ‘functional equivalent’ of a motion or petition to modify.”); Boone v.
Gipson, 920 P.2d 746, 749-51 (Alaska 1996) (explaining that because Rule 90.3(h)(2)
“contains no indication that ‘functional equivalents’ of motions for modification . . .
suffice, we conclude that nothing short of a motion or petition for modification satisfies
the requirement”).
       38
              Millette, 177 P.3d at 266.
                                           -16-                                      7281

would likely be permitted upon motion.”39 “In such cases, the burden remains on the
non-custodial parent to file a motion for modification of child support.”40 We have
further observed that “allowing the court to alter [a parent’s] obligation absent the filing
of a motion for modification would undermine Rule 90.3’s stated goal of ensuring
predictability in determining the amount of child support to be paid.”41
              On the other hand, we recently indicated that a modification of child
support could be effective as of the date of the mother’s motion to modify custody
where, as in Millette, the motion was silent on child support.42 But because the father in
that case “concede[d] that [the mother’s] motion to modify custody satisfied the
[retroactivity] provision of Alaska R. Civ. P. 90.3(h)(2),” it was unnecessary for us to
decide whether Rule 90.3(h)(2) was actually satisfied.43
              Harmonizing these cases requires us to again look at the purposes behind
the retroactivity bar. Rule 90.3(h)(2) restates the federal prohibition of retroactivity
found in the Bradley Amendment, which “specifies what laws a state must have in order
to receive federal funds” for child support enforcement activities.44 Among the Bradley


       39
              Id.
       40
              Id.
       41
              Schofield, 993 P.2d at 408.
       42
              Swaney v. Granger, 297 P.3d 132, 136-37 (Alaska 2013).
       43
              Id. at 137 n.15. Nevertheless we “note[d] that under Rule 90.3(a) the
change of a child’s primary physical custodian from one parent to the other ordinarily
will require modification of an existing support order.” Id.
       44
             Karpuleon v. Karpuleon, 881 P.2d 318, 320 n.6 (Alaska 1994); see also
Alaska R. Civ. P. 90.3 cmt. X.B (explaining that Rule 90.3(h)(3) “is intended to restate
[the Bradley Amendment’s] prohibition”). The Bradley Amendment is shorthand for
                                                                          (continued...)
                                            -17-                                      7281

Amendment’s requirements is that states have procedures ensuring that child support
payments not be “subject to retroactive modification . . . except that such procedures may
permit modification with respect to any period during which there is pending a petition
for modification, but only from the date that notice of such petition has been given . . .
to the obligee or (where the obligee is the petitioner) to the obligor.”45 Discussing the
policy reasons behind the federal retroactivity bar in Karpuleon v. Karpuleon, we noted
commentators’ concerns that evidence was sometimes not “easily attained or available”
to support retrospective arguments about changed circumstances and that obligor parents
should be required to act diligently when petitioning for reductions in their child support
payments.46
              The United States Department of Health and Human Services (DHHS),
responding to comments on the Bradley Amendment’s implementation, repeatedly
emphasized that it is the obligation of the non-custodial parent — who “is in the best
position to know of a change in circumstances” — “to take action promptly to seek
modification of a support obligation.”47 Changed circumstances that trigger the obligor’s
responsibility to act “might include” the fact that “the child [has gone] to live with the




       44
             (...continued)
Section 9103(a) of the Omnibus Budget Reconciliation Act of 1986, 42 U.S.C.
§ 666(a)(9) (2012).
       45
              42 U.S.C. § 666(a)(9)(C).
       46
             Karpuleon, 881 P.2d at 321 (quoting Prohibition of Retroactive
Modification of Child Support Arrearages, 54 Fed. Reg. 15,757, 15,758 (Apr. 19, 1989)).
       47
             Prohibition of Retroactive Modification of Child Support Arrearages, 54
Fed. Reg. at 15,761.
                                           -18-                                      7281

obligor.”48 As relevant here, DHHS reiterated: “We do not . . . believe that . . . even a
change of actual custody of the child should result in a modification of support liability
unless the court or administrative authority is duly notified and sanctions such
modification.”49    And the required notice is the formal notice required by state
jurisdictional rules:
              We believe Congress intended that “date of notice” or “date
              notice is given” should be construed literally and in terms of
              acquiring personal jurisdiction over the other party. State law
              provides rules to determine when personal jurisdiction is
              acquired by service of notice of an action. Under these
              provisions, the “date of notice” or “date notice is given”
              should be interpreted by the State in the same way as it is
              generally applied to commence other civil litigation within
              the State. State law regarding the establishment of the date of
              notice that a petition has been filed dictates when the
              modification may be effective.[50]
              The federal agency comments do not interpret the Bradley Amendment as
dictating the title, form, or substance of the “motion for modification” necessary to
satisfy the retroactivity bar. They focus primarily on the importance of two factors:
(1) notice that child support is at issue, and (2) that the notice be formal — that is, that
it involve the court. In our view, a motion for modification of custody based on an
existing, de facto change in physical custody will usually provide the other parent the
same “fair warning that support may change” as the parent would receive from an




       48
              Id.
       49
              Id.
       50
              Id. at 15,763.
                                           -19-                                       7281

explicit motion to modify child support.51 The requirements of federal law — focusing
on notice and formal process — remain satisfied if the superior court has the flexibility
to choose the date of that custody motion as the effective date for a modification of child
support.52
              In this case, Matthew filed an ex parte custody action in California in early
October 2015 that sought, among other things, a modification of custody to reflect the
parties’ 2014 agreement giving him primary physical custody. Darcey acknowledges
that Matthew informed her in late September that he was taking this action, and he later
filed in Alaska a California “Proof of Personal Service” that showed she had been served


       51
              See Boone v. Boone, 960 P.2d 579, 585-86 (Alaska 1998) (“[S]ervice of the
motion [to modify child support] gives the opposing party both fair warning that support
may change and an opportunity to reassess, even before the court rules, the correct
amount of support. This gives an opportunity to adjust consumption patterns in
anticipation of modification, and thus minimize prejudice when relief is granted effective
as of the service date.”).
       52
              We overrule Millette v. Millette, 177 P.3d 258, 266 (Alaska 2008), to the
extent it would require an explicit request for a change in child support to be included
in a motion for a change of custody before that motion could be used in setting the
effective date for child support. Other cases that have applied the “no functional
equivalents” principle are distinguishable as not involving either modifications of
custody or the formal invocation of judicial process that we require here. In Wright v.
Wright, 22 P.3d 875, 879 (Alaska 2001), the father filed motions to modify child support
but they were rejected as defective; we held that “[w]ithout a valid motion before the
court, a modification of child support would be retroactive and thus prohibited.” In
State, Dep’t of Revenue, Child Support Enf’t Div., ex. rel Husa v. Schofield, 993 P.2d
405, 407-09 (Alaska 1999), the father sought a retroactive change in child support based
on CSED’s implicit agreement that the existing order was erroneous, but “neither CSED
nor [the parent had] filed or served a motion for modification.” In Boone v. Gipson, 920
P.2d 746, 749-51 (Alaska 1996), the mother sought a retroactive change in child support
based on letters from CSED informing the father that it was reviewing his child support;
we held that the earliest document that satisfied Rule 90.3(h)(2) was a formal motion to
modify child support.
                                           -20-                                      7281

with the pleadings on October 8, 2015. At that time the child was already living with
Matthew, and Darcey acknowledges she had actual notice of Matthew’s intent to
formalize their de facto custody arrangement by seeking to modify custody in California.
                We conclude that the superior court did not abuse its discretion when it
selected November 1, 2015 — the first date of the month immediately following the
filing of the California custody action — as the effective date of the new child support
order.
         D.	    The Superior Court Did Not Abuse Its Discretion By Continuing Joint
                Legal Custody.
                Matthew argues in his cross-appeal that the superior court erred by refusing
to modify joint legal custody despite its finding — and both parties’ testimony — that
their communication had broken down. We conclude that this was not an abuse of
discretion.53
                “Joint legal custody is preferred”54 but “is only appropriate when the
parents can cooperate and communicate in the child’s best interest.”55 Thus, “the test for




         53
             Like modifications to physical custody, modifications to legal custody
require a two-prong analysis. Rego v. Rego, 259 P.3d 447, 452 (Alaska 2011) (“Alaska
Statute 25.20.110 authorizes courts to modify child-custody and visitation awards if
(1) there has been a change in circumstances that justifies modification and (2) the
modification is in the best interests of the child.”).
         54
              Jaymot v. Skillings-Donat, 216 P.3d 534, 540 (Alaska 2009) (citing Farrell
v. Farrell, 819 P.2d 896, 899 (Alaska 1991)); Peterson v. Swarthout, 214 P.3d 332, 336
n.6 (Alaska 2009) (citing Bell v. Bell, 794 P.2d 97, 99 (Alaska 1990)).
         55
                Jaymot, 216 P.3d at 540 (quoting Farrell, 819 P.2d at 899).
                                            -21-	                                     7281

evaluating the propriety of joint legal custody is whether or not the parties can cooperate
and communicate regarding the children.”56
               Here, the superior court acknowledged “concerns about the parties’ ability
to communicate” but also found that Darcey and Matthew had communicated “somewhat
effectively” before the current issues arose in the fall of 2015. The court discussed its
“hope that the parties will be able to communicate again, once the current issues are
resolved.”57    We conclude that it was not manifestly unreasonable under the
circumstances for the court to base its decision on that hope, grounded in turn in its direct
experience with the parties.58
V.     CONCLUSION
               We AFFIRM the superior court’s custody and child support orders.




       56
             Farrell, 819 P.2d at 900; see also Jaymot, 216 P.3d at 540 (quoting Farrell,
819 P.2d at 899); Littleton v. Banks, 192 P.3d 154, 161 (Alaska 2008) (“[J]oint legal
custody depends in large part on the ability of the parents to communicate.”).
       57
              See Collier v. Harris, 377 P.3d 15, 21 (Alaska 2016) (affirming a superior
court’s decision not to modify legal custody where “the parties’ ability to communicate,
though not ideal, was not unusual in the circumstances and was adequate to support
continued joint decision-making”).
       58
              Matthew also argues on his cross appeal that the superior court clearly erred
by finding that Darcey was “currently divorcing” her husband. The superior court made
a supplemental finding on this issue later, and we need not address it.
                                            -22-                                       7281

