Your best bet is to read the Medicare manual and see exactly what codes are accepted and what level of care is given. Chapter 10 is the best to read. I do ambulance billing but the really difference is that we do not use CPT codes or exact diagnosis codes. Ambulance is considered ground transport and does fall under a different category (we are neither in or out of network) but it's basically the same.
Most insurances based their allowed amount off the Medicare Fee Schedule.
If you can read this then you're standing too close.