(a) Upon allowance of his claim, claimant or his duly authorized agent shall sign the voucher for payment, Standard Form 1145, before payment is made.

(b) When the claimant is represented by an attorney, the voucher for payment (SF 1145) shall designate both the claimant and his attorney as “payees.” The check shall be delivered to the attorney whose address shall appear on the voucher.

(c) No attorney shall charge fees in excess of 25 percent of a judgment or settlement after litigation, or in excess of 20 percent of administrative settlements (28 U.S.C. 2678).