Let's see, I'm a Bears fan and Mike Martz is currently the OC of the Bears. When asked why Cutler doesn't change plays Martz responded with "No one changes the play in this offense. You get 2 options, and that's it. Warner didn't change any plays in this offense, and either will Jay."
This was said on the radio. I was shocked to hear it as well, but it makes sense. Martz gives 2 options on a play, and the QB basically picks which one based on coverage. There are no at the line audibles if Mike Martz is your OC. Not sure why you think otherwise, but I'm telling you the truth.