Milk sold and distributed outside of this Commonwealth in any state which charges milk dealers or handlers a license fee may be deducted in the determination of the amount of the license fee required by this act, on the condition, that such quantity of milk is actually computed in determining the amount of such license fee in such other state. In computing the license fee to be charged by the board, the fluid milk equivalent of milk other than fluid milk, shall be ascertained and fixed in such manner as the board shall prescribe, except in the case of farm-separated sour cream used exclusively in making butter to be marketed or ultimately sold as such, in which case the total quantity of such milk shall be computed according to pounds of butterfat of sour cream rather than the fluid milk equivalent thereof. Nothing herein is to be construed as requiring, in the computation of the license fee, the inclusion of milk which is received by the applicant milk dealer or handler from another milk dealer or handler, subject to license hereunder, which milk has been included in the computation of such other dealer's fee; or milk which is produced by the applicant dealer or handler and not sold by him to stores or consumers. Applicant milk dealers or handlers, other than subdealers or subhandlers, receiving their entire supply from milk dealers or handlers who have paid a license fee thereon to this board, shall pay the license fee fixed by regulation of the board subject to the act of June 25, 1982 (P.L. 633, No. 181), known as the “Regulatory Review Act.”¹