How about powder burn characteristic changes? Frankly, that seems far more likely to me. I have noticed the same thing between an older electronic manual vs. a current one. My last lot of N133 more closely matched charge ranges from the manual I had from when it was produced vs. the current one. Charge weight vs. velocity matched pretty darned well. That suggests pretty strongly, IMO, that the data changes for today aren't for legal reasons. They're just 'fiddling' with burn characteristics.
Hodgy's been doing the same thing with some of their powders of late, IMO.