(b) The distinctions mentioned in paragraph (a) of this section, depending on whether the acts or omissions complained of occurred before or after May 14, 1947, may be illustrated as follows: Assume that an employer, on commencing performance of a contract with X Federal Agency extending from January 1, 1947 to January 1, 1948, received an opinion from the agency that employees working under the contract were not covered by the Fair Labor Standards Act. Assume further that the employer may be said to have relied in good faith upon this opinion and therefore did not compensate such employees during the period of the contract in accordance with the provisions of the Act. After completion of the contract on January 1, 1948, the employees, who have learned that they are probably covered by the Act, bring suit against their employer for unpaid overtime compensation which they claim is due them. If the court finds that the employees were performing work subject to the Act, they can recover for the period commencing May 14, 1947, even though the employer pleads and proves that his failure to pay overtime was in good faith in conformity with and in reliance on the opinion of X Agency, because for that period the defense would, under section 10 of the Portal Act, have to be based upon written administrative regulation, order, ruling, approval, or interpretation, or an administrative practice or enforcement policy of the Administrator of the Wage and Hour Division. The defense would, however, be good for the period from January 1, 1947 to May 14, 1947, and the employer would be freed from liability for that period under the provisions of section 9 of the statute. The requirements of the statute as to pleading and proof emphasize the continuing recognition by Congress of the remedial nature of the Fair Labor Standards Act and of the need for safeguarding the protection which Congress intended it to afford employees. See § 790.2 ; of. statements of Senator Wiley, 93 Cong. Rec. 4270; Senator Donnell, 93 Cong. Rec. 4452, and Representative Walter, 93 Cong. Rec. 4388, 4389.