One of the big differences between the two measurement systems is "time at pressure". The piezoelectric measurement system looks at the peak pressure value, regardless of the time value, and resulted in reduction of a lot of load data when it was implemented. The crusher system gives a measurement of how much the copper pellet is crushed (obviously), which involves some time value.
Pressure signs with hot AA7 loads are unusual, compared to most other powders, like Blue Dot. With Blue Dot, in my experience, flattened primers show up just a little before, or at the same time, as case bulges or "smiles" show up. With AA7, flattened primers seem to show up waaay before any case bulges. I've gotten flat primers with 12.5-13gr AA7 and a 155gr bulle, but even at that 15gr load above, I haven't seen any sign of case bulging. This is in my LW barrel which has about the same unsupported area as a stock G20 barrel.
This tells me that either 1) the fine AA7 ball powder is leaking into the primer pocket and causing the flattened primers early, and/or 2) that AA7 has a pressure spike that occurs too fast to bulge the brass, even though it may technically be over the pressure limit.