I think with this offense it has to do with understanding and knowledge of the full play book, not just him but everyone so when a play is changed everyone knows what the new play is. As Tyrod says, he is getting more freedom with it, I think that is a reflection of it. I am not going to leap to conclusions about how the brand new offense is going to be run in regards to audibles off of the first two games.
That being said, I hope they let him call audibles sooner rather than later