Hospitals or health systems can't pay physicians like what I think you're describing. A situation where a hospital pays a surgeon extra to do an operation at their facility is illegal.

Sometimes surgeries are hard and a surgeon basically takes it on the chin when you end up spending several hours doing a case which is routinely done in much less time. The surgeon can't really increase charges just because a particular operation was more challenging: you get paid what the insurance company decides to pay. And what they pay is almost completely independent from what you bill (which has no basis in reality or actual costs).

Lightmann's explanation below is the most accurate rationale for the crazy charges that get tagged to hospital and physician bills. There is almost no expectation that any insurance carrier will pay that much, but each carrier pays something different and their rates change all the time without any notice. You can't collect more than you bill, so most practices will bill artificially high figures so they don't undercharge a carrier who might have contractually paid more had the bill been higher.

It's a stupid game that has evolved over decades and is confusing for everyone but the attorneys and accountants.