                 FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,             
                Plaintiff-Appellee,         No. 05-50078
               v.
                                             D.C. No.
                                          CR-04-02162-LAB
TED ALLEN, aka; Ted Alan
Wachtin,                                     OPINION
             Defendant-Appellant.
                                      
       Appeal from the United States District Court
         for the Southern District of California
        Larry A. Burns, District Judge, Presiding

                Argued and Submitted
        November 17, 2005—Pasadena, California

                  Filed January 12, 2006

Before: William C. Canby, Jr., Ferdinand F. Fernandez, and
            Marsha S. Berzon, Circuit Judges.

                 Opinion by Judge Berzon




                            525
528                UNITED STATES v. ALLEN


                         COUNSEL

Norma A. Aguilar, San Diego, California, argued the case and
was on the briefs for the defendant-appellant.

Michelle P. Jennings, Assistant U.S. Attorney, San Diego,
California, argued the case and was on the briefs; Carol C.
Lam, U.S. Attorney, and Roger W. Haines, Jr., Assistant U.S.
Attorney, San Diego, California, were on the briefs for the
plaintiff-appellee.


                         OPINION

BERZON, Circuit Judge:

  Ted Allen was sentenced to twelve months imprisonment
and three years supervised release after a plea of guilty for
counterfeiting. At the sentencing hearing, the district court
applied an enhancement not addressed in the plea agreement.
Because the district court did not make the proper findings in
considering the enhancement, we reverse and remand to pro-
                    UNITED STATES v. ALLEN                    529
vide it the opportunity to do so. We also conclude that the
government did not breach the plea agreement by presenting
a witness at the sentencing hearing as requested by the district
court and questioning him. We therefore affirm the district
court’s decision in that respect.

                       I.   Background

   On September 9, 2004, Ted Allen pleaded guilty to charges
that he “knowingly bought, sold, exchanged, transferred,
received or delivered a false, forged, or altered obligation or
other security of the United States; to wit: counterfeit $100
Federal Reserve Notes; and did so with the intent that the
obligation be passed, published, or used as true and genuine.”
The plea agreement stated that on or about May 25, 2004,
Allen sold fourteen counterfeit $100 bills to an individual
who knew that they were counterfeit. There was no charge in
the superseding information to which Allen pleaded guilty
alleging that Allen had manufactured any of the fourteen
counterfeit $100 bills or possessed any counterfeiting devices
or materials used in connection with them, nor did the plea
agreement address any such allegations.

   The plea agreement stated that the parties would “jointly
recommend” the following guideline calculations:

    1.   Base Offense Level [USSG § 2B5.1]                9

    2.   Increase because Defendant possessed           +2
         or controlled counterfeiting paper
         similar to a distinctive paper

    3.   Acceptance of Responsibility [§ 3E1.1]          -2

    Total Offense Level                                   9

Allen was permitted to request additional departures and
adjustments, and the government was allowed to oppose such
530                     UNITED STATES v. ALLEN
requests. There was a provision in the plea agreement that the
court was not bound by the plea agreement.

   On January 24, 2005, the district court conducted a hearing
on Allen’s sentencing. The Pre-Sentence Report (PSR) pre-
sented at that hearing recommended a total offense level of
fifteen. This recommendation differed from that contained in
the plea agreement because the probation officer who pre-
pared the PSR determined that U.S. Sentencing Guidelines
Manual (Guidelines) sections 2B5.1(b)(2)(A) and (b)(3)
applied.1 Section 2B5.1(b)(2)(A) imposes a two-level increase
on a defendant who has “manufactured or produced any coun-
terfeit obligation or security of the United States, or possessed
or had custody of or control over a counterfeiting device or
materials used for counterfeiting.” Section 2B5.1(b)(3) raises
the total offense level to fifteen if (b)(2)(A) applies and the
resulting offense level is less than fifteen.

   In an effort to determine whether the probation officer’s
recommendation was appropriate, the district court first asked
the prosecutor whether materials used for counterfeiting had
been found at Allen’s residence. When the prosecutor
responded that the search had uncovered a press,2 the district
court asked whether the prosecutor could bring in the secret
service agent who could testify regarding what was found at
Allen’s residence. The prosecutor stated that she could proba-
bly locate the agent. The district court then asked the prosecu-
tor to call the secret service agent to the stand to testify as to
what had been found at Allen’s house. Before doing so, the
prosecutor clarified that the government stood by the recom-
mendation to which it had stipulated in the plea agreement
and that it was the district court that requested the testimony,
stating: “To clarify, the United States is standing by its plea
agreement and standing by its calculations. To clarify, your
  1
    Unless otherwise indicated, all references to the United States Sentenc-
ing Guidelines Manual are to the 2004 edition.
  2
    That response was erroneous, as it turned out.
                       UNITED STATES v. ALLEN                        531
honor, the court would like information from the case agent
regarding whether Mr. Allen had custody and control over a
counterfeiting device or materials used for counterfeiting?”
Defense counsel objected, stating that she “anticipate[d] mak-
ing an argument on breach.”

   Under questioning by both the prosecution and the judge,
the secret service agent, Agent Graf, testified that he and other
agents had discovered in Allen’s trash “shreddings of counter-
feit,” “spray adhesive, the box for a shop press,[3] [and] roll-
ers used to roll out each bill that was glued together.” The
district court then held that the PSR was correct and the calcu-
lation in the plea agreement incorrect. Defense counsel noted
that the Guidelines instruct that 2B5.1(b)(2)(A) is not to apply
“to persons who produce items that are so obviously counter-
feit that they are unlikely to be accepted even if subjected to
only minimal scrutiny.” U.S. Sentencing Guidelines Manual
§ 2B5.1 cmt. n.4. The district court never addressed the argu-
ment. Defense counsel argued that the prosecution had
breached the plea agreement, but the district court rejected the
argument.

   The district court went on to determine that the offense
level was fifteen, based on an enhancement for custody of
materials used in counterfeiting, minus two for acceptance of
responsibility for a total offense level of thirteen. The court
sentenced Allen to the bottom of the Guidelines range, twelve
months, with three years of supervised release. The plea
agreement specifically reserved Allen’s right to appeal if the
sentence was greater than ten months. Allen appeals from this
sentence.
  3
   A “shop press” is “a machine that’s used to press paper together, to
apply a signature on with pressure.” In Agent Graf’s experience, this tool
could be used to manufacture counterfeit bills.
532                 UNITED STATES v. ALLEN
                  II.   Standard of Review

   Allen argues that the district court misinterpreted the
Guidelines in determining his sentence. The district court rec-
ognized that the Guidelines are no longer mandatory but
stated that it was using them as persuasive guidance. As the
district court’s interpretation of the Guidelines essentially
controlled its determination of Allen’s sentence, we review its
interpretation de novo. See United States v. Smith, 424 F.3d
992, 1015 (9th Cir. 2005) (citing United States v. Kimbrew,
406 F.3d 1149, 1152 (9th Cir. 2005)).

   Where the defendant claims that the government breached
the plea agreement and raises an objection to the alleged
breach in the district court, the review is de novo. See United
States v. Mondragon, 228 F.3d 978, 980 (9th Cir. 2000).

          III.   Application of the Enhancement

  A.   Mootness

   [1] Allen was released November 10, 2005, before the
scheduled oral arguments in this case. His three years of
supervised release began then. We have previously estab-
lished, however, that where a defendant has received a sen-
tence that includes a period of supervised release, a challenge
to the length of his sentence of imprisonment is not moot
because the district court has discretion regarding the length
of supervised release, see 18 U.S.C. § 3583(a)-(b), and can
change the supervised release period, see § 3583(e)(2). See
Mujahid v. Daniels, 413 F.3d 991, 994-95 (9th Cir. 2005).

   [2] Here, the district court could resentence Allen to a
shorter term of supervised release in light of a shorter appro-
priate term of imprisonment or to no term of supervised
release. See id. at 994-95 (citing Gunderson v. Hood, 268
F.3d 1149, 1153 (9th Cir. 2001)); United States v. Verdin, 243
                      UNITED STATES v. ALLEN                       533
F.3d 1174, 1178 (9th Cir. 2001).4 A district court must sen-
tence a defendant to supervised release if the statute so
requires, but this statute does not. See 18 U.S.C. § 473. The
length of the imprisonment sentence is therefore not moot.

  B.    The Sentencing Guidelines and Application Note 4

   [3] After considering the PSR, the district court decided
that section 2B5.1(b)(2)(A) applies. As noted, subsection
(b)(2)(A), in conjunction with subsection (b)(3), increases to
fifteen the level of the offense of counterfeiting where the
defendant has “manufactured or produced any counterfeit
obligation or security of the United States, or possessed or
had custody of or control over a counterfeiting device or
materials used for counterfeiting.” The information to which
Allen pleaded guilty alleged only knowing sale of counterfeit
currency, not possession of counterfeiting devices or material.
The district court therefore conducted an evidentiary hearing
regarding whether Allen had possessed counterfeiting devices
or materials, as that additional fact was pertinent in applying
the Guidelines. At the end of the hearing, the district court
found that Allen had possessed materials used for counterfeit-
ing and, applying subsections (b)(2)(A) and (b)(3), held that
the appropriate Guidelines level was fifteen.

   [4] Application Note 4 to section 2B5.1, however, states
that “[s]ubsection (b)(2)(A) does not apply to persons who
produce items that are so obviously counterfeit that they are
unlikely to be accepted even if subjected to only minimal
scrutiny.” U.S. Sentencing Guidelines Manual § 2B5.1 cmt.
n.4. In applying subsection (b)(2)(A), the district court did not
consider the quality of any notes. Allen argues that the district
court therefore erroneously applied the enhancement.
  4
   The Guidelines mandate supervised release only for sentences of more
than one year. See U.S. Sentencing Guidelines Manual § 5D1.1(a).
534                 UNITED STATES v. ALLEN
   Few cases have considered the applicability of Application
Note 4. All of those cases, moreover, addressed an earlier ver-
sion of the Application Note which excluded from subsection
(b)(2)(A) those who “merely photocopy notes or otherwise
produce [counterfeit] items.” U.S. Sentencing Guidelines
Manual § 2B5.1 cmt. n.4 (2000); see also U.S. Sentencing
Guidelines Manual § 2B5.1 cmt. n.3 (1995). The cases inter-
preting the predecessors to present Note 4 concerned enhance-
ments for photocopying counterfeit notes and did not address
the application of Note 4 to those in possession of counterfeit-
ing devices. See, e.g., United States v. Miller, 77 F.3d 71, 76
(4th Cir. 1996); United States v. Taylor, 991 F.2d 533, 535
(9th Cir. 1993); United States v. Bruning, 914 F.2d 212, 213
(10th Cir. 1990).

   Note 4 does not differentiate between the manufacturing
and possession of counterfeiting devices aspects of subsection
(b)(2)(A). Rather, it applies across the board, advising that the
enhancement under subsection (b)(2)(A)—and, consequently,
the offense level of fifteen prescribed by subsection (b)(3)—
“does not apply” to obviously counterfeit currency. As appli-
cation notes to Guidelines provisions must be used in deter-
mining the proper offense level, see United States v.
Hernandez-Sandoval, 211 F.3d 1115, 1117 n.3 (9th Cir.
2000), Note 4 requires consideration of the notes produced
through use of the counterfeiting devices or materials pos-
sessed.

   The government maintains, however, that Note 4 cannot
apply to persons who merely have “custody of or control over
a counterfeiting device or materials used for counterfeiting,”
U.S. Sentencing Guidelines Manual § 2B5.1(b)(2)(A),
because there may be no counterfeit currency for the fact-
finder to scrutinize in deciding whether the items would pass
minimal scrutiny. We are not at liberty to ignore the wording
of the commentary, which is not restricted solely to the “man-
ufactured or produced” language of (b)(2)(A). The Commis-
sion could have subdivided subsection (b)(2)(A) as it did
                    UNITED STATES v. ALLEN                  535
subsection (b)(2)(B), but failed to do so. There is, conse-
quently, no basis in the language or structure of the Guide-
lines for the distinction the government propounds.

   Nor is there a practical problem with applying Note 4 to all
rather than part of subsection (b)(2)(A) sufficient to justify a
less than literal reading of the Note. Cf. County of Santa Cruz
v. Cervantes (In re Cervantes), 219 F.3d 955, 960-61 (9th Cir.
2000) (“[W]hile the plain language of a statute is not always
conclusive, we ignore plain language only when a ‘literal
interpretation would thwart the purpose of the over-all statu-
tory scheme or lead to an absurd result.’ ” (quoting Wilshire
Westwood Assocs. v. Atl. Richfield Corp., 881 F.2d 801, 804
(9th Cir. 1989))).

   [5] Subsection (b)(2)(A) applies only to a defendant who
“had custody of or control over a counterfeiting device or
materials used for counterfeiting.” U.S. Sentencing Guide-
lines Manual § 2B5.1(b)(2)(A) (emphasis added). The “Back-
ground” section of the Guidelines Commentary explains,
“Possession of counterfeiting devices to copy obligations . . .
of the United States is treated as an aggravated form of coun-
terfeiting because of the sophistication and planning involved
in manufacturing counterfeit obligations . . . .” Id. § 2B5.1
cmt. background (emphasis added). Moreover, in amending
subsection (b)(2)(A) in 2001, the Sentencing Commission
reiterated that the intent of the enhancement is to “ensure
some degree of additional punishment for all offenders who
engage in manufacturing activity.” U.S. Sentencing Guide-
lines Manual app. C, amend 618 (2001) (emphasis added).

   [6] Thus, the enhancement was meant to apply only where
there is some linkage to the actual production of counterfeit
obligations. We therefore conclude, on the basis of the lan-
guage of the enhancement and the Commission’s commen-
tary, that the enhancement applies only if the devices or
materials are “used for counterfeiting,” id. § 2B5.1(b)(2)(A)
(emphasis added), by someone. Possession or custody over
536                 UNITED STATES v. ALLEN
devices or materials that could be used for counterfeiting but
have not been does not count.

  The Eleventh Circuit came to the opposite conclusion in
United States v. Castillo, 928 F.2d 1106, 1108 (11th Cir.
1991). That opinion is, however, not persuasive in this case,
because the enhancement provision was amended in 2001 in
a way inconsistent with the result in Castillo.

   Castillo interpreted subsection (b)(2)(A) to apply to posses-
sion of a counterfeit deterrent. See id. at 1107-08. Section
2B5.1 was amended in 2001, however, to add subsection
(b)(2)(B), specifically addressing possession of counterfeit
deterrents. The enhancement to the offense level of fifteen
applies only to (b)(2)(A), not to (b)(2)(B). See U.S. Sentenc-
ing Guidelines Manual § 2B5.1(b)(3). Thus, the provision that
Castillo relied on, subsection (b)(2)(A), no longer applies to
the circumstance to which Castillo applied it. The Commis-
sion provided a lesser enhancement in that circumstance, in
effect rejecting the result reached in Castillo. Further, the
Eleventh Circuit did not have the benefit of the “Reason for
Amendment” discussion that accompanied the 2001 amend-
ment, making clear that subsection (b)(2)(A) is meant to apply
to offenders who “engage in manufacturing activity.” That
commentary confirms that it is crucial that someone have
“used” the device or material possessed by the defendant to
be subject to the enhancement; otherwise there has been no
“manufacturing activity” in which the defendant is engaged.

   Ordinarily, the government’s proof that counterfeit devices
or materials were “used” to produce counterfeit obligations
will consist of the obligations thus produced. In this case, for
example, the government could presumably present to the
court the fourteen counterfeit bills Allen sold, as long as there
is a basis for linking those bills to the materials used for coun-
terfeiting. Where notes were successfully passed to someone
who did not know of their origin, no further testimony on
quality may be necessary. See Miller, 77 F.3d at 76 (declining
                    UNITED STATES v. ALLEN                  537
to apply the exception to the enhancement and remanding to
the district court for factfinding where one of the counterfeit
bills was successfully passed); see also United States v. Stan-
ley, 23 F.3d 1084, 1086 (6th Cir. 1994) (declining to apply the
exception to the enhancement where multiple counterfeit bills
were successfully passed). Here, however, Allen’s bills went
only to a person who knew that they were counterfeit. Expert
testimony could establish the quality of the counterfeit obliga-
tions that particular devices or materials were used to produce
or the likely quality of such obligations if the counterfeits
themselves are for some reason not available.

   We do not, however, decide whether expert testimony is
necessary for this purpose, or whether the court could decide
on the basis of its own perception of the phony currency doc-
uments that they are or are not of such quality that they are
“unlikely to be accepted even if subjected to only minimal
scrutiny.” U.S. Sentencing Guidelines Manual § 2B5.1 cmt. 4.
Our point, instead, is that the nature of the necessary evidence
is the same in all the circumstances covered by the enhance-
ment. Whether the enhancement is based on manufacturing
and production or on possession of counterfeiting devices or
materials, the notes are likely to be available but may not be,
and the notes may be obviously sufficiently realistic that Note
4 does not apply, or there may be need for further evidentiary
proof on the point. Put another way, as the counterfeiting
devices or materials must be “used,” no special evidentiary
problem arises from applying Note 4 as written.

   At oral argument, the government largely abandoned its
contention that Note 4 applies to some but not all of subsec-
tion (b)(2)(A) and instead relied on the narrower proposition
that the burden of proof under Note 4 in establishing the qual-
ity of the counterfeit currency is on the defendant. We do not
agree.

  In general, “the burden of proof falls on the party seeking
to adjust the offense level.” United States v. Howard, 894
538                     UNITED STATES v. ALLEN
F.2d 1085, 1089-90 (9th Cir. 1990) (citing with approval
United States v. McDowell, 888 F.2d 285, 291 (3d Cir.
1989)); see also United States v. Ameline, 409 F.3d 1073,
1085-86 (9th Cir. 2005) (en banc); United States v. Burnett,
16 F.3d 358, 361 (9th Cir. 1994) (“The government bears the
burden of proving, by a preponderance of the evidence, the
facts necessary to enhance a defendant’s offense level under
the Guidelines.”).5 Thus, the defendant does not bear the bur-
den of proof with regard to sentencing enhancements, as it is
not the defendant who is seeking a higher offense level.6 See
United States v. Pimentel-Flores, 339 F.3d 959, 968 (9th Cir.
2003). The government maintains that this basic principle
does not apply here because Note 4 establishes either an
exception or an affirmative defense, and the burden should be
on the proponent of the exception or affirmative defense. See,
e.g., United States v. Culps, 300 F.3d 1069, 1081-82 (9th Cir.
2002).

   This contention fails. The application notes to the Guide-
lines are exactly that—notes about when a particular Guide-
line applies and when it does not. Note 4 so reads: It explains
that subsection (b)(2)(A) “does not apply” to transparently
counterfeit currency, the equivalent of stating that the subsec-
tion applies only to notes that could be taken as real. As the
defendant bears no burden to establish that circumstances
exist in which subsection (b)(2)(A) does apply, he bears no
burden to demonstrate that the counterfeiting devices and
materials he possessed produced or could produce realistic
counterfeits.
  5
     In United States v. Lewis, 979 F.2d 1372, 1375 (9th Cir. 1992), which
distinguished Howard as not pertinent, the question was not the applica-
tion of burdens of proof to determine a factual question but whether the
court, as opposed to the government, could elicit the pertinent evidence.
   6
     It is worth noting that if on remand the government independently
presents an affirmative case for the application of this enhancement, it will
most likely breach the plea agreement.
                        UNITED STATES v. ALLEN                          539
   The government argues that even if the district court was
mistaken in applying the subsection (b)(2)(A) enhancement,
the overall sentence was reasonable. When the district court
calculates the Guidelines incorrectly, however, and then
essentially indicates that its decision is controlled by its incor-
rect calculation, the sentence cannot have been reasonable.7
See Kimbrew, 406 F.3d at 1154 (remanding where the district
court made a legal error in applying an enhancement). We
therefore remand to the district court so it can apply subsec-
tion (b)(2)(A) properly.

   [7] In sum, we hold that Note 4 applies to all of section
2B5.1(b)(2)(A). Where the enhancement is to apply, the judge
must therefore determine whether the quality of the bills for
which the devices or materials were used is sufficiently high
that the bills could plausibly pass as real currency.

         IV.    Compliance with the Plea Agreement

   Allen maintains that the government breached the plea
agreement by participating in the evidentiary hearing regard-
ing the possession of counterfeiting devices or materials
ordered by the district court. The prosecutor, as noted, found
a witness who could provide information supporting the
enhancement, as requested by the district court and ques-
tioned that witness, thereby eliciting information that pro-
vided the basis for a greater sentence than the one upon which
the prosecutor and Allen had previously agreed. Allen argues
that by doing so, the prosecutor went beyond her duty of can-
dor to the court and so undermined its promise in the plea
agreement to recommend an offense level of nine as to breach
the plea agreement. We reject this proposition, with the cau-
  7
    While the district court did indicate that it was not bound by the Guide-
lines, it went out of its way to emphasize their provenance and to compli-
ment those who had devised them. It also indicated that they were “better,
more scientific, [and] fairer” than individualized judicial sentencing. It
then sentenced Allen to the precise term suggested by the Guidelines.
540                    UNITED STATES v. ALLEN
tion that our decision is premised on the distinct facts of this
case, not on any broad sanction of the procedure used here.

  [8] A plea agreement is a contract and is enforced as such.
See United States v. Mondragon, 228 F.3d 978, 980 (9th Cir.
2000); United States v. Johnson, 187 F.3d 1129, 1134 (9th
Cir. 1999). Because the defendant in a plea agreement relin-
quishes his constitutional right to a trial, INS v. St. Cyr, 533
U.S. 289, 321-22 (2001), “[t]he integrity of our judicial sys-
tem requires that the government strictly comply with its obli-
gations under a plea agreement,” Mondragon, 228 F.3d at
981.

  Allen agreed to plead guilty to the superseding indictment.
In exchange, the government agreed to recommend, jointly
with Allen, the offense level of nine with a sentence in the
middle range.8

   Allen does not argue, as he cannot, that the government
should not have answered the district court’s questions.9 “[A]
plea agreement does not bar the government from honestly
answering the district court’s questions. To the contrary, hon-
est response of the government to direct judicial inquiry is a
prosecutor’s professional obligation that cannot be barred,
eroded or impaired by a plea agreement.” United States v.
Maldonado, 215 F.3d 1046, 1052 (9th Cir. 2000). On the
other hand, an “attempt by the government to influence the
  8
     The plea agreement first stated, “The parties will jointly recommend
the following Base Offense Level, Specific Offense Characteristics,
Adjustments and Departures (if applicable) under the Guidelines.” The
resulting calculation was “Total Offense Level 9.” The plea agreement
then stated, “The Parties will jointly recommend that defendant be sen-
tenced to the middle of the guideline range found by the Court.”
   9
     The prosecutor’s answer to those questions was erroneous. She
answered that the trash pull at Allen’s house turned up a shop press, when
it actually only discovered the packaging for a press and materials usable
for counterfeiting. That distinction, however, lacks significance for the
issue before us.
                    UNITED STATES v. ALLEN                   541
district court” to impose a harsher sentence than the one to
which the government agreed in the plea agreement to recom-
mend would violate the agreement. Mondragon, 228 F.3d at
980-81.

   The government’s actions in this case were not an attempt
to persuade the district court to impose a higher sentence. The
prosecutor reiterated the government’s support for a total
offense level of nine and indicated that she was responding to
the district court’s requests only because the court had so
requested. The plea agreement contained no provision forbid-
ding the prosecutor to respond to requests by the district court
or to present evidence when specifically requested to do so.
Nor is there any suggestion at all in this record that the prose-
cutor was in any way responsible for encouraging the proba-
tion officer to include a higher offense level recommendation
than was contained in the plea agreement, or that she induced
the district court to pursue that recommendation.

   Allen argues that the government’s presentation of evi-
dence was more damaging to him than if it had merely
expressed an opinion inconsistent with the plea agreement. He
cites United States v. Boatner, 966 F.2d 1575 (11th Cir.
1992), in support of his position. Boatner, however, held that
when the government volunteers evidence that the plea agree-
ment is inaccurate or incomplete, the government breaches
the plea agreement even if it simultaneously states that it “will
stick to its stipulation” in the plea agreement. See id. at 1579.
In Boatner, the government contradicted the facts in the plea
agreement not in response to questioning by the district court
but rather in response to the defendant’s claim that the facts
in the PSR were incorrect. In this case, however, the govern-
ment did not argue, unprompted, that Allen manufactured the
counterfeit bill. Instead, the government responded to the dis-
trict court’s specific requests.

   [9] Although this court has not addressed this precise fac-
tual scenario, helpful guidance is available from the District
542                 UNITED STATES v. ALLEN
of Columbia Circuit. In United States v. Ahn, 231 F.3d 26
(D.C. Cir. 2000), the court found no breach of the plea agree-
ment where the prosecutor presented and questioned a witness
upon the district court’s request. In Ahn as in this case, the
questioning of the witness provided only the factual material
for the district court to apply an enhancement. See id. at 38.
Ahn concluded that because “[t]he court undoubtedly under-
stood the nature and purpose of this questioning,” there had
been no breach. Id.; see also United States v. Hand, 913 F.2d
854, 856-57 (10th Cir. 1990) (holding that prosecutor’s cross-
examination of the defendant and a witness about defendant’s
involvement in the crime did not breach a promise in the plea
agreement to recommend reduction based on minor role).

   [10] Here, the questioning was neutral and brief, eliciting
only the bare facts of what Agent Graf found in his trash pull.
The district court, aware of the prosecutor’s dilemma, noted
that it “tried to take over some of the questioning there to take
the onus off [the prosecutor] so it’s not looking like she’s
pushing me to do anything rather than find that Mr. Allen is
a lower guideline range.” The district court thus asked the
questions that clarified the investigation revealed scissors;
explained the meaning of “shop press”; and detailed the sig-
nificance of the items found. The prosecutor did not question
the agent on redirect.

   A prosecutor certainly could breach a plea agreement by
questioning a witness in support of a sentence higher than the
one it promised to support, even if such questioning is in
response to a request by the district court. Because the line
between neutral questioning and impermissible advocacy is
thin, district courts should ordinarily conduct the questioning
themselves where they feel it necessary to receive testimony
in support of a sentence different from the one the prosecutor
has agreed to recommend.

  [11] Here, that preferable procedure was not followed. The
combination of some judicial questioning and prosecutorial
                   UNITED STATES v. ALLEN                 543
care to present the testimony neutrally avoided, however, a
breach of the plea agreement. We therefore affirm the district
court’s holding that the plea agreement was not breached.

                      V.   Conclusion

   [12] We reverse and remand for factfinding consistent with
Application Note 4. We affirm the district court’s decision
that there was no breach of the plea agreement.

  REVERSED in part and AFFIRMED in part.
