All fees and commissions heretofore retained by county treasurers in counties of the first class for their own use for services performed by them, as agent of the Commonwealth in collecting the taxes, fees, license taxes, and license fees set forth in section one hereof, shall, after the effective date of this act, be paid into the treasuries of their respective counties at the times such treasurers are required by law to make return of such taxes, fees, license taxes, and license fees to the Department of Revenue of the Commonwealth.