I've seen times where that audible is used before a passing play. Someone correct me if I'm wrong but I think that's just the audible he uses to negate his snap count and tell Mangold to snap the ball on his next call. He usually uses it when the play clock is winding down and going through the snap count would delay the game. Matt Ryan also uses "Express" and others like Peyton use "Hurry Hurry". A problem that I have noticed is his hard count. It's brutal. He can't even fool me with it, I know exactly when the ball is being snapped and I'd have to imagine the defense does too. He's not gonna draw anyone off sides like that, and SOMEHOW the offensive line manages to false start off of it.