(a) If the employee retires or resigns or if his or her employment or period of active duty ends before collection of the debt is completed, offset of the entire remaining balance of the debt may be made from a final payment of any nature, including, but not limited to a final salary payment or lump-sum leave due the employee as the date of separation, to such extent as is necessary to liquidate the debt.

(b) If the debt cannot be liquidated by offset from a final payment, offset may be made from later payments of any kind due from the United States, including, but not limited to, the Civil Service Retirement and Disability Fund, pursuant to §1.1913.