I went back over the three videos that are posted and I see something that is common in younger pitchers and is an indicator that they are not completely and efficiently employing IR; after release there is a hint of a palm up finish. If you are doing a good job internally rotating the arm then the palm/hand should 'close' or rollover as part of the release. For some reason there is a subconscious, built in, program that wants to push the ball into release. I also think that this particular move is associated with 'walking through' the pitch, like they don't quite get the whipping part of the release. This is also a particularly stubborn actlon to change. One thing that has worked for a couple of students is to try and get them to throw a rollover drop/curve, even though they're not actually throwing that pitch the task/goal of putting that type of spin on the ball makes them 'flick' or whip the ball more.