The only people who know if Heaps is changing plays at the line are the coaches and the players in the huddle. Unless someone told Monson, he is just (once again) talking out of his backside.
I work with the local high school and one of the things I havee implemented is the"false audible" where the offense lines up, the quarterback addresses the center, surveys the defense, backs out of center and barks some garbled call that implements some of our usual call terminology. The receivers or backs move around a bit and the play goes on. What the defense couldn't know is that the audible is just jibberish and the entire routine is planned. It puts doubt into the defense, changes the formation, and makes it harder for the defense to decipher our calls.
Other offenses will give the QB a formation and 2 or 3 plays in the huddle, and he only chooses the play after the defense is set--not changing the play, just picking the best out of a few options. That's what BYU has done in the past with Hall and Beck.
So, just because a QB is yelling and players are moving doesn't mean the play isbeing changed.
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