10 USC 2126 - Members of the program: service credit

(a) Service Not Creditable.— 
Except as provided in subsection (b), service performed while a member of the program shall not be counted
(1) in determining eligibility for retirement other than by reason of a physical disability incurred while on active duty as a member of the program; or
(2) in computing years of service creditable under section 205 of title 37.
(b) Service Creditable for Certain Purposes.— 

(1) The Secretary concerned may authorize service performed by a member of the program in pursuit of a course of study under this subchapter to be counted in accordance with this subsection if the member
(A) completes the course of study;
(B) completes the active duty obligation imposed under section 2123 (a) of this title; and
(C) possesses a specialty designated by the Secretary concerned as critically needed in wartime.
(2) Service credited under paragraph (1) counts only for the award of retirement points for computation of years of service under section 12732 of this title and for computation of retired pay under section 12733 of this title.
(3) The number of points credited to a member under paragraph (1) for a year of participation in a course of study is 50. The points shall be credited to the member for one of the years of that participation at the end of each year after the completion of the course of study that the member serves in the Selected Reserve and is credited under section 12732 (a)(2) of this title with at least 50 points. The points credited for the participation shall be recorded in the members records as having been earned in the year of the participation in the course of study.
(4) Service may not be counted under paragraph (1) for more than four years of participation in a course of study as a member of the program.
(5) A member of the Selected Reserve may be considered to be in an active status while pursuing a course of study under this subchapter only for purposes of sections 12732 (a) and 12733 (3) of this title.
(6) A member is not entitled to any retroactive award of, or increase in, pay or allowances under title 37 by reason of an award of service credit under paragraph (1).