RH - I believe the program was 8 weeks total. Good instructor. I believe son gained some positives from it, but also had some issues possibly from it as well as described.
As for the velo increase at that time, I tend to believe that most any focused pitching program aimed at adding velo is going to yield some measurable results. I've read this repeatedly here and elsewhere -- focusing on velo for a prolonged period is going to tend to increase velo somewhat. I think incorporating the concepts into what the pitcher ultimately takes to the mound is more important, and that takes time. BTW, I wasn't suggesting that son grew strictly within the window of the program such that this impacted velo. My point was that year to year, point A to point B, it's difficult to know what is really driving velo gains.
This time a year ago, I was asking the board for input on off season pitching programs... So thought I would share what son did in his Soph off season and our experience with it... FWIW to those at that juncture now.