Reduction of carried forward loss: declarant may pay tax on the reduction now or carry reduced loss and face later tax. Rule 9 allows a declarant disputing reduction of loss or unabsorbed depreciation to choose between including tax on the reduction in the disputed tax and carrying forward the original loss, or carrying forward the reduced amount and paying tax, surcharge, cess and any interest in subsequent years. The written down value of the relevant asset block shall not be increased by the reduction, and if the reduction concerns issues decided in favour of the declarant, only one-half of the reduction is considered in computing the reduced carryforward.