Perhaps it's an issue of QF sending their aircraft all over the place for maintenance. One day the aircraft is maintained in SIN, the next check it has is in HKG, the third check in MNL etc.
I'm no aircraft engineering expert, but friends I know who work in MROs say it's terrible if an airline does that becasue different suppliers have different ways of keeping records etc and sending aircraft to different suppliers each time means that you've to start from scratch and inevitably both the client airline and the suppliers would miss things out as they're getting used to each other's styles, record keeping etc.
Most airlines who outsource stick with one supplier. Eg JAL sticks to ST Aerospace in SIN. They don't send their entire fleet all over the world. Thinking about if from purely a client-vendor viewpoint, it just sounds like a total nightmare to me. How would QF even do quality control on the myriad of MROs they send their aircraft to?