Background: I had sudden severe abdominal pain, so my wife drove me to the nearest hospital (accross the street), where they performed an emergency appendectomy. Three weeks later, I had stomach pain again in the same area, called my surgeon, and he advised I go to the ER as soon as possible for diagnostics. Total bills for both events = $40,000+ ($32,000+ and $8,000, respectively)
The 'gotcha': My insurance (Humana POS) considers this hospital, and all of its services, 'out-of-network'. The difference in deductible between in and out of network is substantial ($1500 vs $4500).
The footwork so far: I spoke with the billing agent at the hospital, she suggested I write an appeals letter to the insurance company requesting that, due to the emergency nature of the services, they be billed as in-network. I have copies of all my medical records to send in as well.
The goal: Get all expenses covered under the in network deductible!
The questions: Has anyone written a successful appeal letter for this or any other similar circumstances? Does anyone have any advice?
Best case scenario is they count the whole thing as in network, worst case is they count half of it and hit me for $6000 total (both deductibles together)

I need to check, though, as there may be a maximum out of pocket coming into play also.
Thanks in advance