Insurance coverage and caps

Hello I have insurance coverage for the Lap-Band procedure for up to $10,000. I was wondering and I couldn't get a straight answer from my doctor about this:

As we all know, the $10,000 cap is not $10,000. If the provider accepts a lower pay for services, it is done by the insurance company at a "reasonable and customary amount". If the total cost of my surgery ends up being $15,000, would I have to pay for the balance of the discounted payment my insurance carrier gives my providers plus the extra $5,000? This may cost me close to the $15,000 price tag since these insurance carriers do not pay providers for too much. Has anyone out there run into this problem?