(1) In this section:
"index number" , in relation to a quarter, means the All Groups Consumer Price Index number, being the weighted average of the 8 capital cities, published by the Australian Statistician in respect of that quarter.
"relevant amount" means the amount specified in paragraph 18(4)(a) or subsection 19(7), (8) or (9), 24(9), 27(2), 29(1) or (3), 30(1) or 137(1).
"relevant year" means the period of 12 months commencing on 1 July 1988 and each subsequent period of 12 months.
(2) Subject to subsection (3), if at any time, whether before or after the commencement of this section, the Australian Statistician has published or publishes an index number in respect of a quarter in substitution for an index number previously published by the Australian Statistician in respect of that quarter, the publication of the later index number shall be disregarded for the purposes of this section.
(3) If at any time, whether before or after the commencement of this section, the Australian Statistician has changed or changes the index reference period for the Consumer Price Index, then, for the purposes of the application of this section after the change took place or takes place, regard shall be had only to the index number published in terms of the new index reference period.
(4) Where the factor ascertained under subsection (5) in relation to a relevant year is greater than one, this Act has effect as if for each relevant amount there were substituted, on the first day of that relevant year, an amount calculated by multiplying by that factor:
(a) if, by virtue of another application or other applications of this section, this Act has effect as if another amount or amounts were substituted for the relevant amount--the substituted amount or the last substituted amount; or
(b) in any other case--the relevant amount.
(5) The factor to be ascertained for the purposes of subsection (4) in relation to a relevant year is the number (calculated to 3 decimal places) ascertained by dividing the index number of the December quarter immediately before the relevant year by the index number for the December quarter immediately before that first - mentioned December quarter.
(6) Where the factor ascertained under subsection (5) in relation to a relevant year would, if it were calculated to 4 decimal places, end with a number greater than 4, the factor ascertained under that subsection in relation to that relevant year shall be taken to be the factor calculated to 3 decimal places in accordance with that subsection and increased by 0.001.