What is your full route, class of travel & status?
The QF page linked is for USA "com/us/en"
The "au" page here, which may be different. https://www.qantas.com/au/en/travel-...d-baggage.html
"International" depends on your point of view.
Australia domestic flights booked in Australia use weight piece base.

In the QF forum there a number of threads on checked baggage allowances. Can be confusing, as not well written. Was better a few year ago, when they had in table form. One of the old QF threads has images of those tables.