Sounds like you had a salesperson that doesn't understand basic EPA stove combustion. Unfortunately neither did the person writing the manual which the storeperson is parroting. The ACC gets pushed in once to start the burn. That's it.
I'm not following this question. The burn rate control (which is just an air control) goes up and down, the ACC pushes in to set the timer.
The acc can pull partially out or all the way out then it can move up.