A New Tax System (Goods and Services Tax) Act 1999
Chapter 4 - The special rules Part 4-4 - Special rules mainly about net amounts and adjustments
Note:Division 142 - Excess GST
142-1 What this Division is about
Excess GST is not to be refunded if this would give an entity a windfall gain.
Refunding excess GST to a supplier will give it a windfall gain if it has already passed on the excess GST in the price of the supply (and not reimbursed the recipient).