(7)Irrespective of anything contained in any other provision of this Act, the profits and gains of an eligible business to which the provisions of sub-section (1) apply shall, for the purposes of determining the quantum of deduction under that sub-section for the tax year immediately succeeding the initial tax year or any subsequent tax year, be computed as if such eligible business was the only source of income of the assessee during the initial tax year and to every subsequent tax year up to and including the tax year for which the determination is to be made.