En-rooter makes some good points in his post.
While some rocket scientist at Qantas tries to save a poofteenth of fuel on a descent they actually cause other problems which can end up costing more money and/or more fuel.
No use bagging the Qantas drivers. They follow the crap dished out as SOPs in the latest fuel "saving" requirements. Let me tell you most would rather use cruising mach into 300 kts as was the case. But as the saying goes,"its their toy and I'll play with it to their rules."
As for flying at FL410, qantas would but they usually have a full load of passengers, unlike the other nice domestic airline.