38 CFR § 1.992 - Procedures for salary offset.
(a)Types of collection. A debt will be collected in a lump-sum or in installments. Collection will be in a lump-sum unless the employee is financially unable to pay in one lump-sum, or if the amount of the debt exceeds 15 percent of the employee's disposable pay. In these cases, deduction will be by installments.
(1) A debt to be collected in installments will be deducted at officially established pay intervals from an employee's current pay account unless the employee and the Secretary agree to alternative arrangements for repayment. The alternative arrangement must be in writing and signed by both the employee and Secretary or designee.
(2) Installment deductions will be made over a period not greater than the anticipated period of employment. The size and frequency of installment deductions will bear a reasonable relation to the size of the debt and the employee's ability to pay. However, the amount deducted for any period will not exceed 15 percent of the disposable pay from which the deduction is made, unless the employee has agreed in writing to the deduction of a greater amount. If possible, the installment payment will be sufficient in size and frequency to liquidate the debt in three years. Installment payments of less than $25 per pay period or $50 a month will be acceptable only in the most unusual circumstances.