28 CFR § 11.7 - Salary adjustments.
The following debts shall not be subject to the salary offset procedures of § 11.8:
(a) Any adjustment to pay arising out of an employee's election of coverage or a change in coverage under a Federal benefits program requiring periodic deductions from pay, if the amount to be recovered was accumulated over 4 pay periods or less;
(b) A routine intra-agency adjustment of pay that is made to correct an overpayment of pay attributable to clerical or administrative errors or delays in processing pay documents, if the overpayment occurred within the 4 pay periods preceding the adjustment and, at the time of such adjustment, or as soon thereafter as practical, the individual is provided written notice of the nature and the amount of the adjustment and point of contact for contesting such adjustment; or
(c) Any adjustment to collect a debt amounting to $50 or less, if, at the time of such adjustment, or as soon thereafter as practical, the individual is provided written notice of the nature and the amount of the adjustment and a point of contact for contesting such adjustment.