Expenditure allocation for income not includible in total income: prescribes apportionment method for direct costs, interest and investment-related charges. Where the Assessing Officer is not satisfied with the assessee's claim regarding expenditure related to income not includible in total income, rule 8D prescribes that such expenditure be the aggregate of: directly attributable expenditure; an apportioned share of interest computed by the formula AxB/C (A = non-attributable interest; B = average value of investments yielding non-includible income; C = average total assets); and an amount equal to one-half per cent of the average value of those investments, with 'total assets' excluding revaluation increases but including revaluation decreases.