HF3000,
I don't think any ATC has blamed you for the speed changes. I know where the speed changes are coming from and it's not directly from the pilots.
I can't tell you exactly when (about 3 or 4 years ago) but overnight Qantas aircraft started climbing at 280 kts. Quite a few ATC's got caught out on the one particular morning I worked. Up until that point QF used to hammer, 300-320 kts. I think your Pilot group were told we knew about it. We knew nothing! There are countless new managers in ASA that knew about this but it wasn't passed on, probably because the MBA has no understanding of the implications.
I really do not care in the end what speed you climb/cruise/descend at. It's the communication process that is the problem. Back in the 'good ole days' ATC's used to run ASA & dare I say it (?) Pilots probably had more say in how things were run. BBQ's were had at the Sydney AACC (when it was one!) and Pilots and ATC's used to chat at these informal gatherings about what was happening, going to happen etc.