247 F.3d 1165 (11th Cir. 2001)
UNITED STATES of America, Plaintiff-Appellee,v.Pedro Pablo MESA, a.k.a. Tito, a.k.a. Pablo Mesa, Defendant-Appellant.
Nos. 99-12265, 99-12672.
United States Court of Appeals, Eleventh Circuit.
April 11, 2001.April 23, 2001.

Appeal from the United States District Court for the Southern District of  Florida. (Nos. 92-08053-CR-JCP, 91-06081-CR-JCP), James C. Paine, Judge.
Before EDMONDSON and MARCUS, Circuit Judges, and RESTANI*, Judge.
EDMONDSON, Circuit Judge:


1
This appeal is about re-sentencings following remand from the appellate court.


2
In addition to reviewing the district court's determination that Defendant-  Appellant was an organizer/leader in the offense conduct under  3B1.1(a) of the  Federal Sentencing Guidelines, this case presents two other questions. First,  must the district court consider an issue at re-sentencing on remand that is not  within the scope of the mandate and which Defendant failed to raise in his prior  sentencing and appeal therefrom? Second, is a defendant eligible at  re-sentencing for a downward adjustment to his offense level under the  Sentencing Guidelines, for his rehabilitation and good behavior while  incarcerated?


3
We conclude that the district court did not err in finding Defendant held an  organizer/leader role in the offense. We also answer both of the other questions  "No." So we affirm Defendant's sentence.


4
In 1992, Appellant-Defendant, Pedro Pablo Mesa ("Defendant") pled guilty to  violations of 21 U.S.C.  846 and 841(a)(1) in the United States District Court  for the Southern District of Florida. He received a four-level upward adjustment  in his offense category under  3B1.1(a) of the Federal Sentencing Guidelines  for his managerial role in the drug trafficking conspiracy. He also received a  two-level downward adjustment for acceptance of responsibility. The result was a  total offense level of 36 and a sentence of 188 months.


5
Before his sentencing, a Pre-Sentence Investigative Report ("PSI") was prepared,  concluding that Defendant was the organizer/leader of the offense charged in  this case. Based on the PSI, the district court determined that Defendant was an  organizer/leader under the Guidelines. Defendant's attorney failed to file a  timely appeal of the sentence.


6
Defendant, pursuant to 28 U.S.C.  2255, filed a Motion to Vacate, Set Aside or  Correct Judgment and Sentence. The district court adopted the magistrate's  Report and Recommendation and granted Defendant's motion on the basis of  "ineffective assistance of counsel," because Defendant's attorney did not file a  timely notice of appeal. The sentence was vacated to allow the district court to  re-sentence Defendant so he could file a timely notice of appeal.


7
In April 1997, Defendant appeared before the district court for his first  re-sentencing (the "1997 Sentencing"). At issue at the hearing was whether  Defendant was an organizer/leader in the offenses charged. After hearing  testimony by a government witness and considering the amended PSI, the court  imposed the same sentence as at the 1992 Sentencing. Despite requests from the  government and Defendant, the court made no specific findings of fact on  Defendant's role in the offense. Defendant objected to the court's ultimate  findings that Defendant was an organizer/leader.


8
On appeal, we vacated the organizer/leader enhancement and remanded to the  district court to make more detailed, specific findings of fact on the question  of whether Defendant was an organizer/leader in the offense. We concluded that  the record amply supported a buyer/seller relationship between Defendant and  Ricky Hill ("Hill")-the government witness-but that the record was "exceedingly  sparse with respect to any control, influence, or leadership exercised by Mesa  over Hill or Hill's associates." United States v. Mesa, 174 F.3d 203, No.  98-4513, slip op. at 4 (11th Cir. Feb. 25, 1999) ("Mesa I"). We "VACATE[D] the  sentence enhancement and REMAND[ED] for further factual findings."1 Id. at 5.


9
In the light of our mandate, Defendant, on 25 June 1999, was re-sentenced again.  (the "1999 Sentencing"). In addition to arguing that Defendant was no  organizer/leader under the guidelines, defense counsel also requested the  district court to award a one-level downward adjustment pursuant to   3E1.1(b)(2) for "timely notifying authorities of his intention to enter a plea  of guilty..." See generally Federal Sentencing Guidelines Manual  3E1.1(b)(2).  Furthermore, defense counsel requested the district court to grant a downward  adjustment for Defendant's good conduct during more than eight years of  incarceration. The district court denied both requests.


10
The district judge made a series of specific findings of fact from which he  determined that Defendant was a leader/organizer under  3B1.1(a) of the  Sentencing Guidelines. Defendant objected and filed a timely notice of appeal.  It is this appeal which is now under review. In this appeal, he advances these  contentions: 1) the district court ignored the law of the case in finding that  Defendant organized or led Hill and other members of Hill's organization; 2)  even if the district court had the authority to find Defendant was an  organizer/leader in the offense, his findings of fact to support this conclusion  were clearly erroneous; 3) the district court improperly failed to award  Defendant an additional-level reduction in his sentencing under  3E1.1(b)(2);  and 4) the district court erred in denying a one-level downward departure for  post-sentence rehabilitation: the district court said the government did not  have proper notice that the defense would request this adjustment.

Leadership Role

11
Section 3B1.1(a) says that "[i]f the defendant was an organizer or leader of a  criminal activity that involved five or more participants or was otherwise  extensive," his offense level should be increased by four levels. U.S.S.G.   3B1.1(a). We have determined that section 3B1.1(a) requires both a leadership  role and an extensive operation. See United States v. Yates, 990 F.2d 1179,  1181-82 (11th Cir.1993). We review the district court's determination of a  convicted defendant's role in the offense as a question of fact subject to a  clearly erroneous standard of review. But, the application of the Guidelines to  the facts is a question of law that we review de novo. See id. at 1182.


12
Defendant argues that the district court's findings of fact are not supported by  record evidence and are, therefore, clearly erroneous.2 The district court found  the following facts based on the Revised PSI as well as evidence presented at  the plea hearing and each of the two resentencings; 1) When Defendant fell  behind on paying Hill's marijuana supplier, James Wooten ("Wooten"), Hill  brought Wooten directly to Defendant to explain the lack of payment; 2)  Defendant was an "officer" and leader of a young woman who stayed in Defendant's  rented house in Kendall and retrieved cocaine for Defendant to show to Hill; 3)  Defendant organized and led at least one other person to unload marijuana from  Hill's vehicles and re-load them with cocaine; 4) Defendant organized and led a  husband and wife who delivered cocaine to Hill in Tennessee; 5) Defendant  organized at least one person to act as an interpreter during drug deals, and 6)  Defendant organized and led Hill and Wooten in that he exercised decision making  authority over them, he claimed, as the source of the cocaine, a greater share  of the profits, he conducted his drug distribution business with them for more  than four years throughout three states and directed others working with Hill on  how marijuana deliveries and cocaine pickups were to be completed. The district  court determined that, along with other facts, this record established, by a  preponderance of the evidence, that Defendant was one of at least two organizers  and leaders of the offenses charged.


13
The district court's findings of fact are not clearly erroneous. Evidence  presented in both the PSI and in testimony by Hill supports a finding that  Defendant controlled and directed the acts of several people involved in the  drug conspiracy. The district court based its conclusion that Defendant was an  organizer/leader on two theories: the court found (1) that Defendant occupied a  leadership role in Hill's organization and (2) that Defendant controlled several  other people in Florida who were part of the trafficking conspiracy taking drugs  to Georgia. If Defendant occupied a leadership role over either one of the two  sets of people, he was correctly subject to the four-level upward adjustment.


14
When we last saw this case, we said that the record evidence indicating that  Defendant was an organizer/leader over Hill and his organization was "sparse."  Mesa I at 5. After we remanded the case for further findings of fact, no  additional evidence was presented to the district court. The district court,  however, did make specific findings of fact about Defendant's role in Hill's  organization. Upon review of the same evidence that we earlier characterized as  "sparse," we are unsure that the district court did not clearly err in finding  Defendant had a controlling position in Hill's organization.


15
We need not decide that issue, however, because we conclude that the district  court properly determined that Defendant controlled a sufficient number of other  people to qualify as an organizer/leader in the offense. The district court  found that Defendant was the organizer and leader of a young woman who stayed at  his house and retrieved cocaine for him, of a husband and wife team who  delivered cocaine to Hill, of at least one interpreter who would aid in drug  transactions, and of at least one person who would load and unload Hill's  vehicle of drugs during transactions. Each of these findings is supported by  evidence presented at the sentencing hearing. So we cannot conclude that the  district court clearly erred.


16
Defendant makes two arguments about the sentencing adjustment. First, he attacks  Hill's testimony as unreliable and insufficiently precise; and he says,  therefore, that the testimony is, under the circumstances,3 "highly suspect."  This argument attacks the credibility of the evidence presented. But the  district court, seemingly, found the evidence credible. See United States v.  Parrado, 911 F.2d 1567, 1571 (11th Cir.1990) (stating that the determinations of  witness credibility are made exclusively by the finder of fact.) We therefore  determine Defendant's argument to be without merit.


17
Defendant next argues that his activities and relationships described to the  district judge did not, as a matter of law, rise to an organizer/leader role. He  relies heavily on United States v. Alred, 144 F.3d 1405 (11th Cir.1998), to  establish that he was not an organizer/leader in this offense. In Alred, we said  that evidence of the defendant's extensive buyer/seller and fronting4  relationships was insufficient to support an enhancement as an organizer/leader.  We noted that evidence of fronting, without more, was insufficient to satisfy  the management requirement and that negotiating deliveries is merely incidental  to a buyer/seller relationship. Id. at 1422. There was also evidence in Alred  that the defendant was caught traveling with another person while in possession  of a large sum of cash, and that he worked with another person to unload  marijuana from a truck. Id. at 1421. In short, no evidence existed of "authority  in the organization that perpetrates the criminal conduct, the exertion of  control, or leadership." Id. at 1422.


18
In contrast, evidence in this case was presented that defendant directed the  activities of several people, including at least three people who stored and  delivered cocaine for him, other people who unloaded and prepacked vehicles, and  at least one interpreter who translated during drug transactions. The cumulative  effect of directing these activities in furtherance of the offense is sufficient  for a sentencing court to find that the Defendant acted as an organizer/leader  for the purposes of U.S.S.G.  3B1.1(a)

One-Level Adjustment for Timely Plea

19
Defendant argues that, at the 1999 Re-sentencing, the district court should have  applied a one-level downward adjustment to his sentencing level pursuant to  U.S.S.G  3E1.1(b)(1) (allowing adjustment for a timely plea). The district  court declined to order the adjustment; the judge said the PSI prepared for the  1999 Re-sentencing recommended only the two-level reduction for acceptance of  responsibility.


20
At one time, Defendant might have been eligible for the one-level adjustment  under Section 3E1.1(b)(1). But we conclude that the district court committed no  reversible error given the surrounding circumstances: 1) the argument for the  adjustment was unrelated to the reason for our remand; 2) it was brought to the  district court's attention for the first time at the 1999 Re-sentencing; 3) it  could have been, but was not, introduced to the district court at the 1997  Re-sentencing,5 4) it could have been raised in Mesa I, although it would have  been subject to a plain error standard of review in Mesa I.


21
If the appeals court issues a specific mandate, the district court must obey:  the mandate is not subject to interpretation. See Litman v. Massachusetts Mutual  Life Ins. Co., 825 F.2d 1506, 1511 (11th Cir.1987) (en banc). In Litman we  pointed out that "[p]ost mandate maneuvering in the district courts would  undermine the authority of appellate courts and create a great deal of  uncertainty in the judicial process... [and] eliminate any hope of finality."  Id. at 1511-12. The district court must implement both the letter and spirit of  the mandate, taking into consideration our opinion and the circumstances it  embraces. See Pelletier v. Zweifel, 987 F.2d 716, 718 (11th Cir.1993) (citing  Piambino v. Bailey, 757 F.2d 1112, 1119 (11th Cir.1985)).


22
In this case, we remanded saying, "we VACATE the sentence enhancement and REMAND  for further factual findings." Mesa I, at 5 (emphasis added). Also, the order of  our court, issued as the mandate, said, "it is now ordered and adjudged by this  Court that the sentence enhancements imposed by the said District Court in these  causes be and the same are hereby VACATED and that these matters be REMANDED to  the said District Court for further proceedings in accordance with the opinion  of this Court." United States v. Mesa, Docket #98-4513, Judgment Feb. 25, 1999  (issued as Mandate Mar. 31, 1999). Our mandate to the district court did not  vacate Defendant's sentence in its entirety and was not related to the argument  Defendant later raised with the district court for a one-level reduction for a  timely plea.


23
Under these circumstances, the district court was not required to consider an  argument which Defendant should have introduced at the 1997 Re-sentencing and,  moreover, should have raised in his first appeal in Mesa I. Requiring the  district court to consider the argument at the second re-sentencing following  our remand would give defendants incentive to introduce sentencing objections in  a piecemeal fashion and would allow them (by their waiting to advance the  argument anew at re-sentencing) to avoid the difficult burden of "plain error"  review in their first appeal. See United States v. Cover, 199 F.3d 1270, 1277  (11th Cir.2000) (sentencing decision not challenged at the district court is  subject to plain error review on appeal).6 No reversible error is presented by  the district court's declining to grant Defendant's late argument for a  one-level reduction under Section 3E1.1(b)(2).

Post-Sentencing Rehabilitation

24
Defendant finally argues that he is entitled to some downward adjustment for his  rehabilitative efforts and good behavior during his years of incarceration.  Although we wonder whether a defendant facing re-sentencing should be eligible  for a downward adjustment for good behavior in prison, we need not address the  question in this case. United States v. Pickering, 178 F.3d 1168 (11th  Cir.1999), clearly prohibits a downward adjustment to Defendant's offense level  under the Guidelines.


25
In Pickering, we held that it was an abuse of discretion for the district court  to adjust a defendant's offense level, as opposed to his criminal history  category, downward for extraordinary rehabilitative acts while awaiting  sentencing. Here, Defendant correctly points out that Pickering involved a  defendant who had not yet been sentenced at all, while this case deals with a  re-sentencing. We view, however, this distinction to be one without a  difference.


26
In Pickering, we analyzed the organizing principles of the Sentencing Guidelines  and concluded that a prisoner's efforts at rehabilitation "reflect more strongly  on the offender's rehabilitative potential and likelihood of recidivism." Id. at  1175 (quoting United States v. Mogel, 956 F.2d 1555, 1560 (11th Cir.1992)). We  concluded, therefore, that any "departure for post-offense rehabilitation must  occur along that (the criminal history) axis." Id. So we specifically rejected  Offense Level adjustment for post-offense rehabilitation.


27
We recognize Defendant's argument that Pickering was a case where the offender  had not yet been sentenced at all. But Pickering's reasoning is persuasive to  us. The concepts underlying Pickering seem equally applicable to offender's  facing re-sentencing. We see no good reason for limiting Pickering's teaching in  the way Defendant suggests. Because Defendant is already at the lowest possible  criminal history category under the Guidelines (category I), he is eligible for  no adjustment for post-offense rehabilitation.

Conclusion

28
We conclude that the trial court was not clearly erroneous in its findings of  fact and that these facts support the determination that Defendant was an  organizer/leader in the offenses charged. We also conclude that this court's  mandate to the district court for the 1999 Re-Sentencing was limited to  determinations of fact for the organizer/leader sentencing level adjustment;  thus, the district court did not err in declining to address Defendant's claim  that he is entitled to a one-level downward adjustment for the timeliness of his  plea. In addition, we extend the Pickering rule and conclude that Pickering does  not allow a downward adjustment to the offense level for a defendant's  post-offense rehabilitation. Although Pickering might allow for a downward  departure in the criminal history level, Defendant's criminal history category  is already at the lowest possible level. He is, therefore, eligible for no  decrease due to his good behavior or efforts at rehabilitation.


29
AFFIRMED.



NOTES:


*
  Honorable Jane A. Restani, Judge, United States Court of International Trade,  sitting by designation.


1
  In remanding the case we noted that the government argued that Defendant could  have been an organizer/leader for purposes of the guidelines due to his control  over others who worked directly for him, but that the district court had given  no indication that it relied on this evidence to conclude that Defendant was an  organizer/leader in the offenses charged. Mesa I at 5.


2
  Defendant's first argument-that our remand to the district court established law  of the case that only a buyer/seller relationship existed between Defendant and  Hill-is without merit. Although we did say that "[t]he record amply supports a  buyer/seller relationship," we did not preclude the district court from  determining, upon further consideration, that Defendant was, in fact, in a  leadership role. Although we wrote that the evidence in the record was  exceedingly sparse for Defendant's control over Hill or Hill's associates, we  did not make a decision on a question of law and did not establish the law of  the case to be that only a buyer/seller relationship could exist between the  two.


3
  Hill was testifying as a cooperating witness and hoped for more lenient  treatment based on his cooperation.


4
  Fronting is when a dealer gives other drugs on credit and is reimbursed once  they sell the drugs to others.


5
  At oral argument Defendant argued that an objection was not made at the 1997  Re-sentencing because the judge had limited the scope of the re-sentencing.  Defendant did, however, file a six-page objection to the PSI for the 1997  Re-sentencing; and he did not object to the PSI's failure to include the  one-level reduction now requested.


6
  Had Defendant raised this issue in his first appeal, he might have been entitled  to some measure of relief on "plain error" review. By failing to appeal the  question at that time, he, however, abandoned this argument. And the district  court, on remand, was not required to consider it when our mandate did not  require a de novo resentencing.


