(12)The tax payable in respect of the under-reported income shall be—(a)where no return of income has been furnished or where return has been furnished for the first time under section 280 and the income has been assessed for the first time, the amount of tax calculated on the under-reported income as increased by the maximum amount not chargeable to tax as if it were the total income;(b)where the total income determined under section 270(1)(a) or assessed, reassessed or recomputed in a preceding order is a loss, the amount of tax calculated on the under-reported income as if it were the total income;(c)in any other case, determined as follows— (X-Y)where,—X = the amount of tax calculated on the under-reported income as increased by the total income determined under section 270(1)(a) or total income assessed, reassessed or recomputed in a preceding order as if it were the total income; andY = the amount of tax calculated on the total income determined under section 270(1)(a) or total income assessed, reassessed or recomputed in a preceding order.
