Central Sales Tax rate increase alters specified sections, substituting a higher percentage and modifying rate application methods. Amendments to the Central Sales Tax Act, 1956 effective 1 July 1975 substitute the rate of 'three per cent.' with 'four per cent.' in the proviso to section 6, in subsection (1) and subsection (2A) of section 8, and in clause (a) of section 15; section 8 is further amended by replacing 'at the rate' with 'at twice the rate' in one clause and by correcting a cross reference within subsection (2A) to clause (b) of subsection (2).