I don't think I'm going to nail this, but perhaps move us in the proper direction?
In my opinion, what OB described is pivot lag, or the kinematic sequence which is what 6-M-1 means to me.
Accumulator lag is angles. A visual would be the angle between left wrist and shaft created when employing the #2 accumulator. You can see Accumulator lag. I think many confuse accumulator lag with a late or "snap" release.
Clubhead lag is pressure. #3 Pressure point would be a great thing to monitor for clubhead lag, that's why the PBS is so popular. You can't see clubhead lag. One of my favorite quotes from YODA came from Alignment Golf:
THE SECRET OF GOLF IS NOT A POSITION IT’S A PRESSURE!
My thoughts, if incorrect I'm looking forward to learning the proper definitions.
Kevin
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I could be wrong. I have been before, and will be again.