Pub. L. 86-707, tit. II, pt. A, sec. 202

Sec. 202. Allowances granted under this title may be paid in advance, or advance of funds may be made therefor, through the proper disbursing officer in such sums as may be deemed advisable in consideration of the need and the period of time during which expenditures must be made in advance by the employee or employees. Any advance of funds not subsequently covered by allowances accrued to the employee or employees under this title shall be recoverable by the Government by setoff against accrued salary, pay, compensation, amount of retirement credit, or other amount due from the Government to such employee or employees and by such other method as may be provided by law for the recovery of amounts owing to the Government. The head of the Government agency concerned may, in accordance with regulations of the President, waive in whole or in part any right of recovery under this section, if it is shown that such recovery would be against equity and good conscience or against the public interest.