((a)) ** .—** Subject to subsection (b), when certified cost or pricing data are not required to be submitted by for a contract, subcontract, or modification of a contract or subcontract, the data may nevertheless be required to be submitted by the head of the procuring activity, but only if the head of the procuring activity determines that the data are necessary for the evaluation by the agency of the reasonableness of the price of the contract, subcontract, or modification of a contract or subcontract. In any case in which the head of the procuring activity requires the data to be submitted under this section, the head of the procuring activity shall justify in writing the reason for the requirement.

((b)) ** .—** The head of the procuring activity may not require certified cost or pricing data to be submitted under this section for any contract or subcontract, or modification of a contract or subcontract, covered by the exceptions in section 3503(a)(1) or (2) of this title.

((c)) ** .—** The head of a procuring activity may not delegate the functions under this section.