I've never seen his fastball as a 60. The stuff is pretty good though, I've seen him live a couple times in A+ ball. I always thought he was a little overrated, not much feel to pitch.
I bet the thought is a release adjustment in an attempt to improve fastball command and velocity. It looks like his fastball is cutting some and that he could pronate a little earlier. Not sure, because the video isn't great, but that'd add velocity and should improve his ability to command the pitch.
He does look like he's lost athleticism from his top prospect days as his body has filled out though.