(a) The Secretary of the Department concerned is empowered to use any means provided by law to recover amounts of annuities erroneously paid to any individual under the Plan. He may authorize such recovery by adjustment in subsequent payments to which the individual is entitled.
(b) There need be no recovery when in the judgment of the Secretary of the Department concerned and the Comptroller General of the United States, the individual to whom the erroneous payment was made is without fault and recovery would be contrary to the purpose of the Plan or would be against equity and good conscience.