((a)) The Secretary of the Army or the Secretary of the Air Force, as the case may be, may allow a member of the National Guard who is not on active duty to make allotments from his pay under sections 204 and 206 of this title for the payment of premiums under a group life insurance program sponsored by the military department of the State in which such member holds his National Guard membership or by the National Guard association of such State if the State or association concerned has agreed in writing to reimburse the United States for all costs incurred by the United States in providing for such allotments. The amount of such costs and procedures for reimbursements shall be determined by the Secretary of Defense and his determination shall be conclusive. All amounts of reimbursements for such costs received by the United States from a State or an association shall be credited to the appropriations or funds against which charges have been made for such costs.

((b)) The United States is not liable for loss or damage suffered by a person as a result of an error made by an officer or employee of the United States in carrying out the allotment program under subsection (a).