Acceleration and velocity are two different things. The cue could be moving at a very high speed and actually be decelerating.
I see the point you're making and it is valid. Thanks for clarifying that.
But in Chris's defense, I think I understand what he is saying and that is that when you decelerate, MOST of the time, your velocity(SPEED) has decreased from what you originally planned for the cue ball and that the reduction of speed from the deceleration of your cue allows the swerve to become more effective.
JoeyA