Appellant is the manufacturer of paper. As a matter of general practice, as found by the Tribunal, appellant dispatches the paper from time to time raising composite invoices setting out the price amount payable, which is inclusive of excise duty. In the transactions involved, which were the subject matter of present appeals, appellant had sold goods to various dealers and collected the invoice amount, which is inclusive of excise duty as applicable at the relevant point of time. Late on, on account of market conditions, the dealers were offered quantitative discounts and other discounts and the invoices were revised accordingly. The scheme of offering discounts was informed to the department from time to time. At the time of clearing the goods from the factory premises, the appellant had paid the excise duty on the invoices amount. Later, when the invoices were revised, the excise duty component, which was collected from the dealers initially, was revised in terms of the revised invoice price, which was lower than the invoice amount, which was initially issued. The difference of amount in excise duty, which was collected, was given credit to the dealers, thereby the actual amount of excise duty collected from the dealers was corresponding to the revised invoices subsequently issued. These facts are not in dispute, as the same were found by the primary authority and also by the appellate authority. There is also no challenge to these findings of fact recorded by the authorities concerned even before the Tribunal and also before this court in the present appeals.