If BYU moves the ball and scores under GRIMES, Kalani won't say a word, he will have his hands full with the defense.
The only reason a head coach may restrict or takeover aspects of the Offense is when they are not getting results with the OC, there is no reason for a head coach to meddle in success and frankly I have so much confidence in GRIMES if he can't get it done, no one can.