38 C.F.R. § 3.713
(b) Persons entitled to pension on December 31, 1978. The effective date of an election to receive improved pension filed before October 1, 1979, by a person entitled to receive either old-law pension or section 306 pension on December 31, 1978, shall be January 1, 1979, or if to the beneficiary's advantage, at any date after January 1, 1979, and before October 1, 1979. The amount of improved pension payable from the effective date of the election shall be reduced by the amount of old-law pension or section 306 pension paid to the beneficiary for such period.
(Authority: Sec. 306(d) of Pub. L. 95-588, 92 Stat. 2497).
[44 FR 45944, Aug. 6, 1979]