((a)) The authorized strengths of the Army, Air Force, and Marine Corps in reserve general officers in an active status, and the authorized strength of the Navy in reserve officers in the grades of rear admiral (lower half) and rear admiral in an active status, are as follows:
((b)) The following Army and Air Force reserve officers shall not be counted for purposes of this section:
((1)) Those serving as adjutants general or assistant adjutants general of a State.
((2)) Those serving in the National Guard Bureau.
((3)) Those counted under .
((4)) Those serving in a joint duty assignment for purposes of chapter 38 of this title, except that the number of officers who may be excluded under this paragraph may not exceed the number equal to 20 percent of the number of officers authorized for the armed force concerned by subsection (a).
((c))
((1)) The following Navy reserve officers shall not be counted for purposes of this section:
((A)) Those counted under .
((B)) Those serving in a joint duty assignment for purposes of chapter 38 of this title, except that the number of officers who may be excluded under this paragraph may not exceed the number equal to 20 percent of the number of officers authorized for the Navy in subsection (a).
((2)) Not more than 50 percent of the officers in an active status authorized under this section for the Navy may serve in the grade of rear admiral.
((d)) The following Marine Corps reserve officers shall not be counted for purposes of this section:
((1)) Those counted under .
((2)) Those serving in a joint duty assignment for purposes of chapter 38 of this title, except that the number of officers who may be excluded under this paragraph may not exceed the number equal to 20 percent of the number of officers authorized for the Marine Corps in subsection (a).
((e))
((1)) A reserve general officer of the Army or Air Force may not be reduced in grade because of a reduction in the number of general officers authorized under subsection (a).
((2)) An officer of the Navy Reserve or the Marine Corps Reserve may not be reduced in permanent grade because of a reduction in the number authorized by this section for his grade.
((f)) The limitations in subsection (a) do not apply to an officer released from a joint duty assignment or other non-joint active duty assignment, but only during the 60-day period beginning on the date the officer departs the joint duty or other active duty assignment. The Secretary of Defense may authorize the Secretary of a military department to extend the 60-day period by an additional 120 days, except that not more than three officers in an active status from each reserve component may be covered by an extension under this sentence at the same time.