Provided that where the duty of excise levi able on the said goods is less than the amount of duty of excise paid on the inputs the extent of exemption shall be restricted to the duty of excise on the said goods." A Further notification was issued on July 14, 1978 and this was in the following terms: "In exercise of the powers conferred by sub rule(1) of rule 8 of the Central Excise Rules, 1944, the Central Government hereby exempts tyres and tubes excluding flaps failing under Item No. 16(1) and 18(3) of the First Schedule to the (1 of 1944) (hereinafter referred to as the specified goods) from so much of the duty of excise leviable thereon (read with any rele vant notification issued under the said sub rule(1) of rule 8 and in force for the time being) as is in excess of (a) eighty seven and a half per cent, of such duty, if produced in any factory which com menced production of the specified goods for the first time earlier than the 1st day of April 1976: and (b) Seventy five per cent of such duty, if produced in any factory which commenced pro duction of the specified 201 goods for the first time on or after the 1st day of April, 1976, subject to the conditions that: There is no controversy regarding evaluation According to the assessee as well as the department effect has first to be given to the notification dated August 1, 1974 and the duty calculated in terms of that notification.