Irrespective of fees and charges prescribed in the foregoing sections, the Administrator may enter into contracts with applicants to perform inspection services pursuant to the regulations in this part and other requirements as prescribed by the Administrator in such contract, and the charges for such inspection services provided for in such contracts shall be on such basis as will reimburse the Agricultural Marketing Service of the Department for the full cost of conducting such inspection service, including an appropriate overhead charge to cover as nearly as practicable administrative overhead expenses, as may be determined by the Administrator.