34 Pa. Code § 9.106 : LABOR AND INDUSTRY — Department Of Labor And Industry — Employment and Wages — PREVAILING REGULATIONS — Payment of general prevailing minimum wage rates

(a) Not less than the general prevailing minimum wage rates determined by the Secretary under the act and this subchapter may be paid unconditionally, by contractors and subcontractors to workmen in their respective crafts and classifications on public work and the workmen can not be required to refund, directly or indirectly, part of the wages. It is no defense that workmen accepted or agreed to accept less than the required rate of wages or voluntarily made refunds, in any form or manner.
(b) Wages shall be paid without deductions except authorized deductions. Employers not parties to a contract requiring contributions for employee benefits which the Secretary has determined to be included in the general prevailing minimum wage rate shall pay the monetary equivalent thereof directly to the workmen.
(c) Payment of compensation to workmen for work performed on public work on a lump sum basis or a piece work system or a price certain for the completion of certain amount of work or the production of a certain result shall be deemed a violation of the act and this subchapter, regardless of the average hourly earnings resulting therefrom.

34 Pa. Code § 9.106