Expenditure disallowance rules: insertion linking section 58 to section 40A(12) alters treatment of specified expenditures. Insertion of a new sub-clause (ia) into clause (a) of section 58(1), immediately after sub-clause (i), to include 'any expenditure of the nature referred to in sub-section (12) of section 40A,' with effect from 1 April 1986, thereby bringing such expenditures within the items enumerated in clause (a) of section 58(1).