[Yoda]

Inspired by your post, I opened the yellow book. I think 6-F-0 Timing - General sheds some light too:

... "So, the Clubhead is not picking up speed during the Overtaking (release) Interval, either when Hitting or Swinging."

Remember, as Mike O pointed out in a post last year, Homer Kelley is not referring here to the Clubhead's Surface Speed (miles per hour). That Speed does indeed increase during Release. However, because of the Flat Left Wrist, Angular Speed, i.e., Hand Speed versus Clubhead Speed as measured in revolutions Per minute around the Left Shoulder Axis, does not increase. A readily understood example of Angular Speed is that exhibited by the various components of a merry-go-round all rotating at the same RPM around a common axis.

For the Swinger, after the initial Acceleration in the Start Down, Angular Speed is constant from Release until Impact. For the Hitter, the deceleration begins immediately at Release. For both Swinger and Hitter, the Impact collision slows Angular Speed and Surface Speed.