Woomera, you don't NOt make provisions in the accounts, you simply vary the amount you provide. And since a "provision" is by nature an amount retained against uncertain future events, the exact amount is for management to discuss.
For example, Telstra in the past hid most of its profits through massive depreciation charges.
Qantas could make its $900+ million profit disappear if it suited it. We have no way of knowing if the figure is reasonable and given the calibre of the Board, anything is possible.
As for QF being a large respected Australian Public Company, so was HIH!