((a)) The Secretary of a military department may issue to a disbursing official or agent of the department a requisition for an advance of not more than the total appropriation for the department. The amount advanced shall be—
((1)) under an “account of advances” for the department;
((2)) on a proper voucher;
((3)) only for obligations payable under specific appropriations;
((4)) charged to, and within the limits of, each specific appropriation; and
((5)) returned to the account of advances.
((b)) A charge outstanding in an account of advances of a military department shall be removed by crediting the account of advances of the department and deducting the amount of the charge from an appropriation made available for advances to the department when—
((1)) relief has been granted or may be granted later to a disbursing official or agent of the department operating under an account of advances and under a law having no provision for removing charges outstanding in an account of advances; or
((2)) the charge has been—
((A)) outstanding in the account of advances of the department for 2 complete fiscal years; and
((B)) certified by the head of the department as uncollectable.
((c)) Subsection (b) does not affect the financial liability of a disbursing official or agent.