Question about the football itself

[rockyroad]

A question about the balls used during the game - we had a game Saturday night and the weather was pretty sloppy. We were trying to change balls every play (as much as we could). The HS where I coach is vey small, so we don't have a huge budget...we have three game balls, all three were checked and OK'd prior to the game...two are leather and one is composite. At halftime, the U told us that if we switched from a leather to the comp ball during the same offensive series, he would flag us 15 yards for USC...I have never heard anything like that before - I understand you can't do that when kicking - switch to a specific ball, but between first down and second down? I looked at the white hat and he just shrugged and walked off. Any thoughts?