The following paragraph is substituted for paragraph (b) of section 109(17) of the Principal Act:
"(b) where the amount calculated in accordance with paragraph (a) is a multiple of 5 cent but not also a multiple of 10 cent, be rounded up to the nearest 10 cent, and where the amount is not a multiple of 5 cent or 10 cent, be rounded to the nearest 10 cent.".