(1) Where under this Act, the duty of excise is chargeable on any excisable goods with reference to value, such value shall, subject to the other provisions of this sec tion, be deemed to be (a) the normal price thereof, that is to 1028 say, the price at which such goods are ordi narily sold by the assessee to a buyer in the course of wholesale trade for delivery at the time and place of removal, where the buyer is not a related person and the price is the sole consideration for the sale: Provided that (i) where, in accordance with the normal practice of the wholesale 'trade in such goods, such goods are sold by the asses see at different prices to different classes of buyers (not being related persons) each such price shall, subject to the existence of the other circumstances specified in clause (a), be deemed to be the normal price of such goods in relation to each class of buyers ;" Proviso (iii) to section 4(1)(a) of the Act enjoins that: "where the assessee so arranges that the goods are generally not sold by him in the course of wholesale trade except to or through a related person, the normal price of the goods sold by the assessee to or through such related person shall be deemed to be the price at which they are ordinarily sold by the related person in the course of wholesale trade at the time of removal, to dealers (not being related per sons) or where such goods are not sold to such dealers, to dealers (being related persons) who sell such goods in retail.