Seems like an overly complex auto thrust system that is just waiting to catch you out. Some interesting sub-text to the report. The crew were feeling tired but ok to fly. Had they been given an option to off load themselves in Sydney without any risk of management backlash would they have? The companies response was to institute another layer of procedures by requiring a new TOLD card.
Nothing about flight deck interruptions or the casual way 22 passengers are dumped on their lap. This is not the first time a QF badged aircraft has had an issue with extra passengers loaded and a consequent mishandling of performance figures.