Just an update. My 15 yo son is playing 18U Fall Ball. The head coach is also the local community college pitching coach. He told me my son has very good mechanics. I mentioned the drop in velocity. He thought his 4 seam was moving upper 70's and the 2 seam was mid 70's. He also said my boy held the 2 seam with his fingers split apart more than normal which caused the ball to slow down but also added alot of movement. My son told me he's been holding the ball like that all year. Regardless, he's been pitching against some of the best hitters in the county and he's been sitting them down. I guess whatever works.