I finally figured out what I was doing wrong. Trying too hard.
I don't think I need to go into what I was doing wrong more than that. It occured to me in studying the illustrations that I had read too much into the roll over wrist lock. It was much more simple.
My firing today was, I think, a lot closer to Fist-Fire. Every shot with this technique brought the sights back into alignment. At one point I noticed that my sights were back on target before I heard the spent casing hit the floor.
I ran through several different 9mm for a box of 50 then switched to .40 S&W for another box of various makes and models. Even my XDSC .40 behaved. I did torque one of the 5 rounds off to the left but that's a big improvement for that pistol. 1 round out of 5 an inch to the left at 25 feet. Used to be 5 rounds 5 inches to the left of point of aim at that range.
This was still sighted fire. I haven't begun to experiment with the more advanced concepts. The basic building block of this system is in the grip and support hand.
Tomorrow I'm taking a basic NRA class. The instructor is a former SWAT instructor. I would prefer to take his intermediate course but that's not available until March and I want to get my CCW paperwork in. Better a very basic class I probably don't need and a CCW in my hands in April than paperwork for the CCW turned in by April.