(a) The Administrator, pursuant to the authority vested in him by the Secretary of Labor, will make and apply findings under section 13(b)(11) of the Act as provided in this part. Such findings shall be made only upon petitions meeting the requirements of this part, and only as authorized in this section.

(b) For the purpose of establishing whether a wage payment plan has the purpose and effect required by section 13(b)(11) for an exemption from the overtime provisions of the Act, the Administrator shall have authority, upon a proper showing and in accordance with the provisions of this part, to make a finding as to the general purpose and effect of any specific plan of compensation on the basis of trip rates or other delivery payment plan, with respect to the reduction of the length of the workweeks worked by the employees of any specific employer who are compensated in accordance with such plan for their employment by such employer as drivers or drivers' helpers making local deliveries.

(c) Any finding made as to the purpose and effect of such a wage payment plan pursuant to a petition therefor will be based upon a consideration of all relevant facts shown or represented to exist with respect to such plan that are made available to the Administrator. A finding that such plan has the general effect of reducing the hours worked by drivers or drivers' helpers compensated thereunder to, or below, the maximum workweek applicable to them under section 7(a) of the Act is not authorized under this part unless the Administrator finds that during the most recently completed representative period of one year (based on the experience of the employer in question, or if such employer has not previously used such plan, on the experience of another employer using such plan under substantially the same conditions, all as defined in § 551.8(g)(1)), the average weekly hours, taken in the aggregate, of all full-time employees covered by the plan are not in excess of the maximum workweek applicable to such employees under section 7(a), or unless the Administrator makes an interim finding with respect to such plan that, notwithstanding a lack of experience under it for a representative period of 1 year, its provisions and manner of operation, together with the other available information concerning the plan, indicate clearly that by the end of such first representative year the effect of the plan will have been to reduce the average weekly hours worked by the employees covered by the plan in such first year of operation to, or below, such maximum applicable workweek.