I eventually got the bill to the insurance company reduced by half. It took a year and we still had to pay the same amount.
That’s because they have a contract with the insurance company in which no matter how much they charge, the insurance company only pays what their contract allows. The hospital already knows what the insurance allows, so they tell you what your part will be even before they bill insurance. At least with medicare, you only pay 20% of what medicare ALLOWS the hospital to charge you, not what the original bill is.
That was not actually the reason in our case. The insurance company didn't give a rat's behind because the city I worked for was self-insured... they just paid the insurance company to administer the health care costs on a percentage basis. The more they payed out the more they got to keep. Our expenses were fixed because we only had to pay up to a certain amount in a year.
I felt it was my responsibility to keep the city from being ripped off. I was partially successful.