(a) If an employee retires or resigns before collection of the debt is completed, offset of the entire remaining balance may be made from a final payment of any nature to such extent as is necessary to liquidate the debt.

(b) Where debt cannot be liquidated by offset from final payment, offset may be made from later payments of any kind due from the United States inclusive of Civil Service Retirement and Disability Fund pursuant to 5 U.S.C. 8347 and 5 CFR 831.1801 et seq of this regulation.