This is not a thing. You cannot simply continue surgery with less anesthesia. The issue here is that CMS has guidelines for the anesthesia requirements for different procedures, and anesthesiologists have become notoriously for surprise billing for much higher amounts than those guidelines.
Again: this is a dispute about bills patients don't pay. The most routine imaginable surgeries --- appendectomies, laparoscopic gall bladder removals --- all have average costs that greatly exceed average out-of-pocket caps for insurance.
CMS is far from authoritative on what it takes to keep a particular individual under. The practitioner is ultimately the one with authoritative knowledge. CMS is not in the operating theater.
Now if what we need is to deal with a rash of insurance fraud, insurers are more than welcome to hire people to sit in on the theater to gain more representative data. But let's be real here. Insurance is more interested in improving their take home spreadwise rather than improving patient outcomes.
And I beg to differ it doesn't happen. I remember quite vividly my wisdom teeth being extracted. I was just under threshold for being able to do anything about it, but awake and aware for the entire thing. Anaesthesia is not something to screw around with.
CMS is Medicare. Your wisdom tooth extraction was almost certainly not really general anesthesia. Were you intubated? During an extraction? I doubt it.
Same here for my wisdom tooth but very clearly remember them mentioning there were two options (one like you described and one where I would be out completely). Absolutely zero connection to the current discussion.
d) Stop the anaesthesia and continue the procedure with you regaining consciousness.