The officer or agency empowered to entertain claims under sections 4309(a), 4329, and 4331 of this title shall have power to hold such hearings as may be deemed necessary; to prescribe rules and regulations governing the form and contents of claims, the proof thereof, and all other matters related to proceedings on such claims; and in connection with such proceedings to issue subpenas, administer oaths, and examine witnesses. Such powers, and any other powers conferred upon such officer or agency by sections 4309(a), 4329, and 4331 of this title may be exercised through subordinate officers designated by such officer or agency.