Personally as an offense I would think if you can throw the defense off and gain an upper hand by calling multiple audibles it's a good thing...
I don't remember him doing that at Tennessee but perhaps he did.
Irregardless it works; the guy is playing out of his mind this year and has taken his game to a level most QB's would love to be at.
I think it's well documented that few in the league are as studious as Peyton is. I think he's just trying to get an edge and he obviously is successful.