((a)) ** .—** The Secretary of Defense may credit refunds attributable to Department of Defense managed travel programs as a direct result of official travel to such operation and maintenance or research, development, test, and evaluation accounts of the Department as designated by the Secretary that are available for obligation for the fiscal year in which the refund or amount is collected.

((b)) ** .—** Refunds credited under subsection (a) may only be used for official travel or operations and efficiency improvements for improved financial management of official travel.

((c)) ** .—** In this section:

((1)) ** .—** The term “managed travel program” includes air, rental car, train, bus, dining, lodging, and travel management, but does not include rebates or refunds attributable to the use of the Government travel card, the Government Purchase Card, or Government travel arranged by Government Contracted Travel Management Centers.

((2)) ** .—** The term “refund” includes miscellaneous receipts credited to the Department identified as a refund, rebate, repayment, or other similar amounts collected.