Income tax amendment increases deduction threshold and extends cross-reference to additional subsection with retrospective and prospective effect. The amendment substitutes a higher monetary ceiling in the proviso to section 24(2) of the Income tax Act with effect from 1 April 1997, and inserts a reference to sub section (3) of section 23 after the existing reference to sub clause (i) of clause (a) of sub section (2) of section 23, that insertion being deemed effective from 1 April 1995.