I think this is pretty typical for all insurers now. All insurance companies have negotiated rates with all of the doctors and facilities in their "preferred provider" networks. Anyone without insurance or from another network or who doesn't have the particular procedure covered is charged much more. Perhaps Medicare pays even less than most insurers.
The thing that is hard to understand is how there could be enough uninsured people with income or assets to shift the costs to.
I recently saw a case where some medical tests were paid by an insurance company at 10% of the billed amount and the lab accepted this. The amount paid seemed low. But the billed amount was vastly higher than one could buy the tests for from an independent supplier on the Internet. This tells me that it really does not cost a lot to run many medical lab tests and there is a lot of overcharging and cost-shifting going on in this area.
It tells me that, as with every other market that the federal government has entered, they have managed to pervert it -- destroying the relationship between cost and price.
The identical thing has happened in higher education, where tuition costs have risen so as to soak up every federal dollar available.
And, famously, the mortgage market -- where Fannie Mae and Freddie Mac managed to not only destroy the relationship between cost and price, they managed to destroy the entire market.
Yet, our political elite cannot keep their hands off the free market -- they are hell-bent on de-constructing the source of our prosperity.