(1) For the purposes of this Part, the indexation factor for a financial year is to be worked out using the following formula— where—
"index number" , for a quarter, means the All Groups Consumer Price Index Number (being the weighted average of the 8 capital cities) published by the Australian Bureau of Statistics for that quarter;
"most recent March year" means the period of 12 months ending on 31 March in the immediately preceding financial year;
"previous March year" means the period of 12 months immediately preceding the most recent March year;
"quarter" means a period of 3 months ending on 31 March, 30 June, 30 September or 31 December.
(2) The result worked out under subregulation (1) must be rounded up or down to 3 decimal places, rounding up if the result ends in 0.0005.
(3) A calculation under subregulation (1) is to be made—(a) using the index numbers published in terms of the most recently published reference base for the Consumer Price Index; and(b) disregarding index numbers that are published in substitution for previously published index numbers (unless the substituted numbers are published to take account of changes in the reference base).