The Administrator shall contribute to the employees’ compensation fund, on the basis of annual billings as determined by the Secretary of Labor, for the benefit payments made from such fund on account of employees engaged in carrying out functions financed by the revolving fund established by
section 633(c) of this title. The annual billings shall also include a statement of the fair portion of the cost of the administration of such fund, which shall be paid by the Administrator into the Treasury as miscellaneous receipts.