Income tax exemption amendments modify eligibility and provisos, shifting entry and effective dates for specified instruments and clauses. Amendments effective 1 April 2006 alter Income Tax Act exemption provisions by omitting a second proviso in one sub clause, substituting a later entry cutoff for certain agreements, replacing a singular explanation reference with alternative explanations under distinct sub sections, omitting an earlier timing reference in a qualifying item, and substituting a later effective date in a proviso to change transitional applicability.