The provisions of this section shall also apply to the insurance of any mortgage under sections
1715v,
1715w, or
1715z–1 of this title except that compliance with such provisions may be waived by the Secretary in cases or classes of cases where laborers or mechanics, not otherwise employed at any time on the project, voluntarily donate their services without full compensation for the purpose of lowering the costs of construction and the Secretary determines that any amounts thereby saved are fully credited to the nonprofit corporation, association, or other organization undertaking the construction. The provisions of this section shall also apply to the insurance of any mortgage under section
1715y
(d) of this title. The provisions of this section shall also apply to the insurance of any mortgage under section
1715z–7 of this title, except that compliance with such provisions may be waived by the Secretary in cases or classes of cases where laborers or mechanics, not otherwise employed at any time on the project, voluntarily donate their services without compensation for the purpose of lowering the costs of construction and the Secretary determines that any amounts thereby saved are fully credited to the nonprofit corporation, association, or other organization undertaking the construction; and each laborer or mechanic employed on any facility covered by a mortgage insured under section
1715z–7 of this title shall receive compensation at a rate not less than one and one-half times his basic rate of pay for all hours worked in any workweek in excess of eight hours in any workday or forty hours in the workweek, as the case may be. The provisions of this section shall also apply to the insurance of any mortgage under subchapter IX–B of this chapter; and each laborer or mechanic employed on any facility covered by a mortgage insured under such subchapter IX–B shall receive compensation at a rate not less than one and one-half times his basic rate of pay for all hours worked in any workweek in excess of eight hours in any workday or forty hours in the workweek, as the case may be.