A New Tax System (Goods and Services Tax) Act 1999
You have a decreasing adjustment if:
(a) you made a * creditable acquisition in relation to which you had an * increasing adjustment under section 21-15 for a debt; and
(b) you pay to the supplier of the thing you acquired the whole or a part of the amount written off, or the whole or a part of the amount that has been * overdue for 12 months or more, as the case requires.
The amount of the decreasing adjustment is 1/11 of the amount recovered.