It really depends on your insurance company and what your T charges. I receive a statement from my insurance company about all bills. T bills $140 per session my insurance company pays $41 and I pay $20....dd's T charged $100 a session. I have never seen T without having insurance but I know she would work something out with me. Because she has a private practice she pays somebody to do her billing where as if I just paid a flat out price then she wouldn't have to do with that added expense.

One thing which doesn't really have to do with your question but just something. T can write off the difference between what is paid by me and insurance and what is billed on her business taxes. So in my T's case she can write off the $79...in your sliding scale scenario T can write off the difference as well.