A commissioned officer in the service of a military department under section 3061 of this title may, upon the recommendation of the Secretary of the military department concerned, be temporarily promoted to a higher rank or grade.

A commissioned officer in the service of the Administration may be temporarily promoted to fill vacancies in ranks and grades caused by the transfer of commissioned officers to the service and jurisdiction of a military department under section 3061 of this title.

Temporary appointments may be made in all grades to which original appointments in the Administration are authorized, except that the number of officers holding temporary appointments may not exceed the number of officers transferred to a military department under section 3061 of this title.