(c) Use of funds. The Contractor may withdraw funds from the special account only to pay for properly allocable, allowable, and reasonable costs for direct materials, direct labor, and indirect costs. Other withdrawals require approval in writing by the administering office. Determinations of whether costs are properly allocable, allowable, and reasonable shall be in accordance with generally accepted accounting principles, subject to any applicable subparts of part  31 of the Federal Acquisition Regulation.