Central Excise Rules, 2017
Rule 5. Date for determination of duty and tariff valuation.-
The rate of duty or tariff value applicable to any excisable goods shall be the rate or value in force on the date when such goods are removed from a factory or a warehouse, as the case may be.
Explanation.- If any excisable goods are used within the factory, the date of removal of such goods shall mean the date on which the goods are issued for such use.