For OON they reduce the fee to U&C which is patient responsibility, we then get help of patient and file appeal. Yes I've not lost one appeal yet for full reimbursement. Mostly I appeal the higher surgical fees. I do Mental health for group that is non par with Aetna. Since I have other pediatric clients, many times we see full billed fee after appeal. Pre-billing we usually get a precertificaion done for surgical claims and then we let patient know our fee is $XX more and proceed to tell them of our appeal process and they are very cooperative.