5 U.S.C. § 5344
(b) Retroactive pay is payable by reason of an increase in rates of basic pay referred to in subsection (a) of this section only when—
For the purpose of this subsection, service in the armed forces includes the period provided by statute for the mandatory restoration of the individual to a position in or under the Government of the United States or the government of the District of Columbia after he is relieved from training and service in the armed forces or discharged from hospitalization following that training and service.
(Added Pub. L. 92–392, § 1(a), , 86 Stat. 568.)
Provisions similar to those comprising subsec. (a) of this section were contained in Pub. L. 89–554, , 80 Stat. 471 (formerly classified to section 5343 of this title) prior to the general amendment of this subchapter by section 1(a) of Pub. L. 92–392.
Section effective on first day of first applicable pay period beginning on or after 90th day after , see section 15(a) of Pub. L. 92–392, set out as a note under section 5341 of this title.