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       United States Court of Appeals
                  FOR THE DISTRICT OF COLUMBIA CIRCUIT




Argued April 7, 2003                              Decided May 2, 2003

                               No. 02-5193

                      P. HAMILTON BROWN, ET AL.,
                             APPELLEES

                                     v.

              UNITED STATES OF AMERICA AND
   JOHN W. SNOW, SECRETARY, DEPARTMENT OF THE TREASURY,
                       APPELLANTS

                        DISTRICT OF COLUMBIA,
                              APPELLEE



                           Consolidated with
                              No. 02-5194



         Appeals from the United States District Court
                  for the District of Columbia
                         (No. 98cv01282)
                           –————

 Bills of costs must be filed within 14 days after entry of judgment.
The court looks with disfavor upon motions to file bills of costs out
of time.
                             2

   Robert D. Kamenshine, Attorney, U.S. Department of Jus-
tice, argued the cause for appellant. With him on the briefs
were Roscoe C. Howard, Jr., U.S. Attorney, and William
Kanter, Deputy Director.
  Michael J. Kator argued the cause and filed the brief for
appellees.
  Before: SENTELLE and ROGERS, Circuit Judges, and
SILBERMAN, Senior Circuit Judge.
  Opinion for the Court filed by Circuit Judge ROGERS.
  Concurring opinion filed by Senior Circuit Judge
SILBERMAN.
   ROGERS, Circuit Judge: This case concerns the Treasury
Department’s attempt to overcome the conceptual incompati-
bility of two statutes. Specifically at issue is Treasury’s
selection of a ‘‘weighted national average’’ methodology to
calculate locality pay increases under the Federal Law En-
forcement Pay Reform Act of 1990 (‘‘FLEPRA’’), incorporat-
ed as Title IV of the Federal Employees Pay Comparability
Act of 1990, Pub. L. No. 101–509, 104 Stat. 1389 (1990)
(codified at 5 U.S.C. § 5304 (2000)), for retired Uniformed
Division Secret Service agents who receive annuities under
the District of Columbia Police and Firefighters Retirement
and Disability Act (‘‘DCRA’’), D.C. Code Ann. § 5–701 et seq.
(2001). The conceptual difficulty arises because locality pay
increases are geographically fixed while the DCRA’s equaliza-
tion provision is based on the salary of an agent in active
service. Notwithstanding the fact that Secret Service agents
have postings throughout the United States and overseas,
Treasury has determined that locality pay applies to DCRA
Secret Service retirees. Hence, no issue is before the court
regarding the entitlement of those retirees to locality pay
adjustments. Rather, when Treasury determined it would
apply the ‘‘weighted national average’’ methodology, a num-
ber of DCRA Secret Service retirees filed suit, and the
district court invalidated Treasury’s methodology. Brown v.
Summers, 201 F. Supp. 2d 60, 63–64 (D.D.C. 2002). Trea-
sury, joined by the United States and the District of Colum-
                               3

bia, appeals that judgment and contends that in light of the
conceptually difficult task of calculating locality pay increases
for retirees that track those of active agents, Treasury’s
methodology is fair and valid. We hold, first, that Treasury –
as opposed to the District of Columbia – is the proper locus of
decisionmaking for calculating the amount of locality pay for
Secret Service retirees who have opted to retire under the
DCRA. We hold second, that whether viewed as filling a gap
in the DCRA’s equalization clause or as resolving an ambigui-
ty arising from the confluence of two statutes, Treasury’s
methodology is entitled to deference under Skidmore v. Swift
& Co., 323 U.S. 134, 139 (1944). Accordingly, we reverse.

                               I.
   In Floyd v. District of Columbia, 129 F.3d 152, 154 (D.C.
Cir. 1997), the court recounted Congress’ determination that,
in light of the Secret Service’s unique ties to the District of
Columbia Metropolitan Police Department, Secret Service
agents who performed non-clerical duties related to the pro-
tection of the President for ten or more years could convert
their retirement from the Federal Employee Retirement
System, 5 U.S.C. § 8401 et seq. (2000), to the higher-paying
plan governed by the DCRA, D.C. Code Ann. § 5–701 et seq.
See D.C. Code Ann. § 5–703. Unlike the federal system,
which provides for cost-of-living adjustments, 5 U.S.C.
§ 8462, the DCRA contains an ‘‘equalization clause’’ that
automatically increases retired agents’ pensions each time
active agents receive salary increases. The equalization pro-
vision provides:
    Each individual retired from active service and entitled
    to receive a pension relief allowance or retirement com-
    pensation under subchapter I of this chapter shall be
    entitled to receive, without making application therefor,
    with respect to each increase in salary, granted by any
    law which takes effect after the effective date of the
    District of Columbia Police and Firemen’s Salary Act
    Amendments of 1972, to which he would be entitled if he
    were in active service, an increase in his pension relief
                                4

     allowance or retirement compensation computed as fol-
     lows: His pension relief allowance or retirement compen-
     sation shall be increased by an amount equal to the
     product of such allowance or compensation and the per
     centum increase made by such law in the scheduled rate
     of compensation to which he would be entitled if he were
     in active service on the effective date of such increase in
     salary.
D.C. Code Ann. § 5–745(c) (emphasis added).
   Locality pay for Secret Service agents was first authorized
by Congress when it enacted FLEPRA in 1990. Under
FLEPRA, federal law enforcement officials, including active
members of the Secret Service, are paid a percentage of
‘‘basic pay’’ in addition to their rate of pay under the General
Schedule to reflect the higher cost of living in specified
geographic areas. Since 1994, employees in twenty-eight
cities have received locality pay increases, which the Office of
Personnel Management (‘‘OPM’’) adjusts annually. 5 U.S.C.
§ 5304 and note.
   In May 1998, certain retired Secret Service agents, who
were employed as criminal investigators at the time of their
retirement and whose annuities are governed by the DCRA,
filed suit against Treasury, the United States, and the Dis-
trict of Columbia (collectively ‘‘the government’’), claiming
that locality adjustments awarded to active agents pursuant
to FLEPRA were ‘‘increases in salary’’ subject to the
DCRA’s equalization clause. The district court dismissed the
case without prejudice in December 1998, subject to reopen-
ing within six months, when Treasury agreed to include
locality pay increases in the retirees’ annuities. Letter of
December 9, 1998, from Nancy Killefer, Assistant Secretary,
Dep’t of Treasury, to Earl Cabbell, Interim Chief Financial
Officer, District of Columbia (‘‘the Killefer letter’’), reprinted
in Joint Appendix (‘‘J.A.’’) at 110–15. The case was reopened
in July 1999, when the retirees had not received locality pay
increases.
  Treasury subsequently determined it would award each
retiree locality pay increases based on a ‘‘weighted national
                               5

average’’ of locality adjustments for active Secret Service
agents since 1991. The calculation under this methodology
was based on the locality pay increases paid to active Secret
Service agents throughout the United States, weighted to
reflect the number of agents actually serving in each locality
receiving increases. Treasury then awarded lump sum back
payments to all DCRA Secret Service retirees, and used the
‘‘weighted national average’’ method to adjust annuity bene-
fits for 1999 and each subsequent year. Although this meth-
od benefitted some retirees, others would have fared better
had the locality pay increase been determined by the location
of their last post of duty. In January 2000, the district court
granted the motion of plaintiff retirees’ counsel to withdraw
due to the ‘‘irreconcilable’’ conflict of interest between the
retirees.
   In May 2000, retirees who were disadvantaged by the
‘‘weighted national average’’ methodology appeared before
the district court with new counsel, who filed an amended
complaint claiming that the locality pay increases reflected in
their DCRA retirement benefits should be computed on the
basis of the locality pay in effect at their last post of duty.
The district court denied the government’s motion to dismiss,
and ruled, on cross-motions for summary judgment, that
Treasury’s ‘‘weighted national average’’ methodology was not
entitled to judicial deference under Chevron U.S.A., Inc. v.
Natural Res. Def. Council, Inc., 467 U.S. 837, 843 (1984), or
Skidmore, 323 U.S. at 139. Brown, 201 F. Supp at 62–63.
The court concluded that the District of Columbia, rather
than Treasury, is responsible for DCRA’s implementation,
and that the plain language of DCRA’s equalization clause
‘‘requires individualized calculations based on factors individu-
al to each retiree.’’ Id. The court invalidated Treasury’s
method, but declined to replace it with the ‘‘last post of duty’’
method, explaining that the latter ‘‘is without any specific
support in the language of the statute,’’ and that the ‘‘plain-
tiffs’ way is not the only way to comply with the statute’s
mandate of individualized determinations.’’ Id. at 63. The
court entered partial summary judgment for the retirees and
remanded the case to Treasury and the District of Columbia
                               6

to ‘‘fashion a method that complies with the statute.’’ Id. at
63–64.

                                II.
   On appeal, the government contends, as it did in the
district court, that Treasury’s ‘‘weighted national average’’
methodology deserves deference under Chevron, 467 U.S. at
843, or alternatively, deference equal to its power to persuade
under Skidmore, 323 U.S. at 139. Either position requires
the court to determine whether (1) Treasury – as opposed to
the District of Columbia – is the locus of decisionmaking with
regard to locality pay for DCRA Secret Service retirees, and
(2) the DCRA plainly prohibits the use of a ‘‘weighted nation-
al average’’ to calculate locality pay increases for such retir-
ees.
   Although a remand order does not usually signify a final
decision for purposes of conferring jurisdiction on this court
under 28 U.S.C. § 1291 (2000), NAACP v. United States
Sugar Corp., 84 F.3d 1432, 1436 (D.C. Cir. 1996), the court
may exercise jurisdiction ‘‘where the agency to which the case
is remanded would have no opportunity to appeal after the
proceedings on remand.’’ Los Angeles v. Shalala, 192 F.3d
1005, 1012 (D.C. Cir. 1999) (quoting Occidental Petroleum
Corp. v. SEC, 873 F.2d 325, 330 (D.C. Cir. 1989), cert. denied,
530 U.S. 1204 (2000)). Because the district court invalidated
Treasury’s method for calculating locality adjustments, and
remanded with instructions to select a new methodology,
which Treasury views as ‘‘a new choice from among what [it
has] considered to be less desirable alternatives,’’ Appellant’s
Br. at 4, Treasury contends, and we agree, that this appeal
represents its only opportunity to challenge the district
court’s ruling. Therefore, the court has jurisdiction under
the exception recognized in Shalala, 192 F.3d at 1012, and
Occidental Petroleum, 873 F.2d at 330.

                             A.
 In Floyd, the court left open the question of whether the
United States or the District of Columbia is responsible for
                                7

making substantive decisions about Secret Service annuity
adjustments under the DCRA. Floyd, 129 F.3d at 156.
Then, as now, the District of Columbia asserted that ‘‘the
United States makes all substantive decisions about Secret
Service pensions under the DCRA and that the District
serves as a mere conduit for federal pension monies.’’ Id.
The court in Floyd noted, however, that it found nothing in
the DCRA or the record explicitly limiting the District of
Columbia to a passive role. Id. By contrast, the record in
the instant case indicates that the District of Columbia does
not make substantive decisions about Secret Service annuities
under the DCRA, but instead has a role that is ‘‘purely
ministerial, not discretionary.’’ D.C.’s Mem. in Supp. of
Motion to Dismiss. Although the District of Columbia issues
annuity payments to Secret Service retirees under the
DCRA, it has no financial stake in the amount of those
payments, which are determined by the United States and
reimbursed to the District of Columbia by the United States.
See D.C. Code §§ 5–703, 5–732. As the District of Columbia
told the district court, it ‘‘simply acts as an administrator’’ of
the annuity program, ‘‘and is, at most, a conduit for those
federal funds, paying them out as the federal government
directs.’’ D.C.’s Mem. in Supp. of Motion to Dismiss. Trea-
sury agrees with this position, and the District of Columbia
filed a statement in this appeal that its ‘‘interest is adequately
served by the United States.’’ None of the parties suggest
that a federal agency other than Treasury is the proper locus
of decisionmaking or is responsible for funding annuities for
DCRA Secret Service retirees.
  The Killefer letter, relied on by the retirees, is not to the
contrary. Indeed, the letter emphasizes the extent to which
Treasury controls decisionmaking related to DCRA annuities
for Secret Service retirees. Noting that ‘‘questions have been
raised TTT concerning annuities’’ under the DCRA, Treasury
advised the District of Columbia of its conclusion that ‘‘locali-
ty pay TTT is sufficiently akin to salary that it should be
included in the calculation of retirees’ annuity increases.’’
The letter further requests that ‘‘the District [of Columbia]
not alter any current practice with respect to implementation
                              8

of this retirement system without prior discussions with
[Treasury],’’ and explains that Treasury will ‘‘assist the Dis-
trict of Columbia in determining how best to calculate in-
creased annuities based on locality pay.’’ If the District of
Columbia were making substantive decisions about Secret
Service annuities under the DCRA, as the retirees contend, it
would be illogical for the District of Columbia to require
Treasury’s authorization before changing its practices with
regard to annuity payments. The Killefer letter thus sub-
stantiates that Treasury – as opposed to the District of
Columbia – makes substantive decisions about Secret Service
annuity adjustments under the DCRA.
   While there may be joint actions by the United States and
the District of Columbia to ensure that DCRA Secret Service
retirees receive their benefits, and this is likely to entail
cooperative arrangements, the financial control and the sub-
stantive determination, based on an interpretation of a sepa-
rate federal law such as FLEPRA, rests with the United
States – in this case Treasury – not the District of Columbia.
When Congress authorized certain Secret Service agents to
opt into the DCRA, it neither required the District of Colum-
bia to assume the costs of paying the benefits for these
additional annuitants, nor authorized the District of Columbia
to determine the amount of those benefits arising under
separate federal statutes. See D.C. Code §§ 703, 732. What
the parties’ conduct demonstrates is consistent with the Dis-
trict of Columbia having neither a regulatory role nor a
financial stake in the determination of locality pay increases
for DCRA Secret Service retirees. This, in turn, is consistent
with Congress’ decision to afford a generous retirement op-
tion for certain agents at federal expense. D.C. Code
§ 5–703. The district court erred in finding otherwise.

                              B.
  This court is not presented with the question of whether,
pursuant to the DCRA’s equalization clause, federal DCRA
annuitants are entitled to FLEPRA locality adjustments. In
Lanier v. District of Columbia, 871 F. Supp. 20 (D.D.C.
                               9

1994), the district court ruled that under the equalization
clause, DCRA Secret Service retirees are eligible for locality
pay increases given to active agents receiving such adjust-
ments under FLEPRA. Id. at 24; see also District of
Columbia v. Tarlosky, 675 A.2d 77, 80–81 (D.C. 1996). That
the government did not appeal the decision in Lanier does
not alone prove its acquiescence in the judgment. Hastings
v. Earth Satellite Corp., 628 F.2d 85, 94 n.27 (D.C. Cir. 1980).
Nor, inasmuch as the instant appeal arises from a different
lawsuit, is Treasury barred by law of the case or waiver from
challenging eligibility. Crocker v. Piedmont Aviation, Inc.,
49 F.3d 735, 739–40 (D.C. Cir. 1995). Rather, its subsequent
determination in the Killefer letter represents Treasury’s
position that Secret Service DCRA annuitants are entitled to
locality pay adjustments, as the Lanier court ruled; it is on
that determination that Treasury, as well as the United
States and the retirees, relies in the instant case. Hence, the
government has waived any challenge to the entitlement of
DCRA Secret Service agents to locality pay.
   The conceptual difficulty underlying Treasury’s contention
that the court should defer to its selection of a payment
methodology underscores, however, that DCRA’s equalization
provision hardly appears to have been designed with locality
pay in mind. Congress enacted the DCRA in 1916, and
amended it in 1957 to allow participation by retired Secret
Service agents. See Pub. L. No. 85–157 § 12(b), 71 Stat. 391,
392 (1957). Neither enactment indicates that Congress antic-
ipated the adoption of FLEPRA in 1990 or the incorporation
of locality pay increases into the DCRA. Nor did this change
with enactment of the District of Columbia Retirement Pro-
tection Act of 1997, which provided a cost-of-living adjustment
for retired D.C. Metropolitan Department police officers and
D.C. firefighters under the DCRA, but expressly declined to
amend the DCRA as it applied to Secret Services retirees.
Compare Pub. L. No. 105–33, 111 Stat. 251, § 11013 (1997),
with id. at § 11084(c).
   The district court in Lanier aptly stated that there is a
‘‘clash of two worthwhile principles,’’ one to ensure retirees
are treated fairly in their retirement and one to provide
                               10

locality pay incentives to ensure adequate public protection.
871 F. Supp. at 23. The equalization clause provides that
each Secret Service retiree shall receive an increase in his
annuity equal to any increase in salary ‘‘to which he would be
entitled if he were in active service.’’ D.C. Code § 5–745(c)
(emphasis added). Because active Secret Service agents
move frequently, and sometimes to less desirable postings
justifying additional salary incentives, any individual retiree’s
locality pay adjustment is by necessity a fictitious extrapola-
tion of what ‘‘he would be entitled [to] if he were in active
service.’’ Id. The district court here recognized that if a
DCRA retiree ‘‘is receiving a percentage increase equal to
what he or she would have received as an active agent today,
[ ] it is merely by coincidence.’’ Brown, 201 F. Supp. 2d at
63.
   Given the strange gap in the DCRA, a gap that Congress
may not have intended to leave but one the court must
address in light of Treasury’s determination to award locality
pay increases to DCRA Secret Service retirees, the court is
unable to conclude that the DCRA’s plain language prohibits
Treasury’s ‘‘weighted national average’’ methodology, much
less that it requires only ‘‘individual determinations,’’ as the
district court ruled. Any sense that the DCRA was intended
to include locality adjustments is betrayed by the fact that,
because of the movement of Secret Service agents’ duty
assignments to over one hundred offices throughout the
United States and overseas, no methodology can provide
every retiree with the exact locality adjustment he would
have received as an active agent. Indeed, to the extent the
district court ruled that individualized locality adjustments
were required, the government points out that:
    there is no way to ascertain the locality increase that the
    agent would actually receive if currently employed.
    Thus, all methods of adjustment are inherently flawed in
    terms of the ‘‘individualized’’ determination envisioned by
    the district court. And no method of approximation, no
    matter its merits, will be equally advantageous to all
    retirees.
                               11

Appellant’s Br. at 14. Further, there is no merit to the
retirees’ attempt to distinguish between ‘‘room for applica-
tion’’ and ‘‘ambiguity’’ arising from the confluence of the two
statutes so far as the extension of deference to Treasury’s
methodology. In either circumstance, the DCRA must be
construed to permit the exercise of reasonable judgment in
closing the gap or resolving the ambiguity.

                             C.
   The question remains whether Treasury’s ‘‘weighted na-
tional average’’ methodology is entitled to judicial deference.
The government challenges the district court’s ruling that
Chevron deference is unavailable where, as here, Treasury’s
methodology was promulgated informally during the course
of litigation, without notice-and-comment rulemaking.
Brown, 201 F. Supp. at 62. Because we hold that Treasury’s
methodology satisfies the requirements for Skidmore defer-
ence, however, 323 U.S. at 139, we need not reach the
question of Chevron deference.
   Under Skidmore, the court grants an agency’s interpreta-
tion only as much deference as its persuasiveness warrants.
Id. In making its determination, the court must examine
‘‘the thoroughness evident in [the agency’s] consideration, the
validity of its reasoning, its consistency with earlier and later
pronouncements, and all those factors which give it power to
persuade, if lacking power to control.’’ Id. at 140; cf. Chris-
tensen v. Harris County, 529 U.S. 576, 587 (2000). Trea-
sury’s methodology for calculating locality pay increases satis-
fies the requirements for Skidmore deference.
  The record demonstrates that Treasury examined five dif-
ferent methods for calculating locality pay increases before
choosing the ‘‘weighted national average’’ methodology: (1)
the annuitant’s last post of duty; (2) the annuitant’s resi-
dence; (3) the average of all locality pay rates across the
country; (4) the locality pay rate in the District of Columbia;
and (5) the ‘‘weighted national average.’’ Treasury analyzed
the various outcomes of each methodology, and noted, for
example, that if the last post of duty was used, as the retirees
                              12

urged before the district court, ‘‘annuitants who retired from
certain localities would not have received any locality pay
increase.’’ Treasury officials also consulted the OPM and
engaged in discussions with the District of Columbia to devise
appropriate procedures for effecting the increases before
making its selection.
   Moreover, Treasury’s choice of the ‘‘weighted national aver-
age’’ method reflects its reasoned attempts to choose a calcu-
lation that mirrors the actual career experiences of agents
moving from one locality to another. Although the govern-
ment concedes that the use of averaging reduces the adminis-
trative burden associated with other methods, the affidavits
from various Treasury officials, including the Supervisory
Personnel Management Specialist and the Deputy Assistant
Secretary for Human Resources, demonstrate that the princi-
pal reason for choosing that technique is that it is the ‘‘most
equitable approach because all annuitants would receive some
increase each year, regardless of where they might happen to
have last worked or where they presently live.’’ Treasury
further explained that it ‘‘did not consider using more than
one method of calculating locality pay increases for annui-
tantsTTTT [because it] believes that the equalization provision
and basic fairness require that a single method be applied to
all annuitants.’’ Moreover, Treasury noted, the use of a
single annual percentage increase across the board is similar
to across-the-board increases under many other retirement
systems.
  Finally, Treasury has ‘‘specialized experience’’ in calculat-
ing annuities, particularly those under the administratively
complex DCRA. United States v. Mead Corp., 533 U.S. 218,
234–35 (2001) (internal citation omitted). The Killefer letter
indicates that Treasury regularly evaluates how other federal
statutory schemes effect the DCRA annuity system, and often
makes decisions about what national law requires.
  In light of the fact that no locality adjustment can give the
retirees exactly what they would be paid as active agents,
Treasury’s ‘‘weighted national average’’ methodology is a
                            13

persuasive solution to an unforeseen problem, and for all of
the above reasons, it is entitled to Skidmore deference.
  Accordingly, we reverse the judgment of the district court
invalidating Treasury’s methodology.
                                1

  SILBERMAN, Senior Circuit Judge, concurring: I think
Judge Rogers has ably analyzed the case before us, and I
concur in the court’s opinion. I write separately because I
would go a step further and conclude the statute does not
even cover locality pay. As such, the only possible challenge
appellees could make under the APA to Treasury’s determi-
nation that locality pay should be averaged for these Secret
Service retirees is that the Treasury was arbitrary and
capricious. They did not do so, and I do not see how such a
challenge could have been successful.
  I agree with the majority that it is certainly not open to us
to hold that locality pay is not available to Secret Service
Agents who chose to receive annuities under the DCRA. The
Treasury Department acquiesced in the district court’s ruling
in Lanier v. District of Columbia, 871 F. Supp. 20 (D.D.C.
1994), to the effect that those retirees were entitled to locality
pay increases under the equalization clause–as it was entitled
to do. Accordingly, the government sought to accommodate
that ruling by adopting the weighted average methodology.
It did not even suggest in this case that the locality pay
statute does not apply to appellees.
  Still, we are not obliged, for purposes of this case, to accept
the Lanier district court construction of the locality pay
statute. It seems rather obvious to me, as the majority
suggests, that the very fact that no one can even propose a
persuasive methodology, including the district judge below,
by which locality pay would apply to appellees demonstrates
that Congress never intended locality pay to cover them.
That is why the statute is silent on the issue.
