Also remember that as the 767's come toward the end of their useful life, much of their early life was spent doing medium to long range intetnational routes. So at that part of their life, they may be operating up to 16 hours a day of flying time, but only 2 flights (4 cycles).

So these aircraft may be getting very high in operating hours, but nowhere near their limits of cycles. So QF can delay some heavy maintenance work (like D checks which are very expensive) by moving them onto domestic ops and reducing the daily operating hours while working lots of cycles.

This helps to even out the maintenance requirements and extent the time between major maintenance costs.

Another issue is that airlines pay landing, registration and other fees based on the maximum weight capability of the aircraft, not based on the actual takeoff or landing weight. The A332's when operating short-haul domestic ops are very light due to the low fuel requirement compared with their fuel carrying capability. So QF are paying higher fees while not operating at the weights they are paying for.

For this reason, QF had some of their 767's registration weight reduced so their fees would also be reduced. I remember reading somewhere that some of their aircraft (may have been 747's but could be 767's) had two registration weights and they have had two plaques that had to be swapped inside the flight deck depending on the operating weight in order to pay the correct fees.