That's Standard Operating Procedure: Ignore all bills until you get the EOB. True whether you have high or low deductible or some or no copays.
What I was saying was that with a low deductible policy, one can recognize something is amiss without adding up the EOB's. This can't be said for HD policies.
Say you add up all of the "you might owe" from Medicare, and subtract out the amount that your supplemental policy paid and the net was $500. And the provider says you owe $700. What do you do?
If you pay the $500, they send the $200 to collections, and it's your problem.
I wouldn't pay a dime until the bill agrees with Medicare, but I'm not sure how responsive the hospital billing department is going to be if you just come in with "I should only owe $500 according to Medicare". They'll probably just keep sending the $700 bill. And according to my state DOI rep, pretty much everyone just gives up and pays the extra if it isn't "too much."