On and after
July 1, 2008, or such earlier date as the Secretary of Defense may prescribe, a person covered by section 1475 or 1476 of this title may designate one or more persons to receive all or a portion of the amount payable under
section 1478 of this title. The designation of a person to receive a portion of the amount shall indicate the percentage of the amount, to be specified only in 10 percent increments, that the designated person may receive. The balance of the amount of the death gratuity, if any, shall be paid in accordance with subsection (b).