Usually when you see insurance companies that pay 90% or 80%, there is a deductable and then it pays ie. 80% of the bill until the maximum yearly out of pocket, that is preset, is reached, and then usually most plans cover at 100% after that.
This usually applies to lesser bills, not big ones.
So, let's say you have a $100,000 NICU bill, you have a $1,000 yearly deductable, coverage at 90% and a yearly out of pocket maximum of $5,000, the most you are going to pay is $6,000.
But let's say you have a bill that is $4,500. You still pay your $1,000 yearly deductable, and insurance pays 90% of the remaining $3,500, so they are going to pay $3,150, so in the end you'll end up paying $1,350 of a $4,500 bill.
Obviously, all insurance companies are different, but more often than not, when you see the the coverages, it generally doesn't mean that is all they cover, but there are some fly-by-night insurance companies that only cover the 90% or 80% and that's it...and to me, they are not even worth paying the premiums for.
Luckily, when the bankruptcy laws changed, you can bankrupt medical bills the same as before....it's the credit card, student loans and other types of debts that the new bankruptcy laws cracked down on and they are very, very difficult to get.
I also know that many, many hospitals, also forgive extremely large debts and take it as a tax write off.
My daughter was in for 2 months and the bill, at my calculation, was over $130,000 for both the hospital and the doctors. My insurance, that was excellent, paid every last dime, I didn't even have a deductable because I used an in-network facility and doctor (going out of network, is just NOT worth it, if the doctor isn't on my plan, I find another one, yeah, you might like the doctor, and they might be really good, but they are not the only good doctor in town). I always, always, get the MAXIMUM coverage that my employer provides, because all it takes is one incident like mine, one car accident, one bout with cancer, and you will be worrying more than about getting well.