I can't quite tell if your question is about how much she gets paid, or how much your copay is. The two things are not related to each other. The copay is set by BCBS, and so you'll just have to talk with her about how to minimize that. If all you're paying is a copay, what does it matter what BCBS reimburses her for?

I'm not an insurance expert, but I strongly doubt she gets reimbursed for $150. She probably gets $75 or $90 or something like that. It probably says on your BCBS statement. For instance, my T charges $200 per appointment, which is what you would pay if you're uninsured. If you are insured, he gets about $90 instead, plus the copay. As far as I'm concerned he can ask BCBS for as much as he wants; my copay isn't going to change, unless the number of sessions or billing code changes (or BCBS decides to change it).

I'm sure she'll be happy to talk to you about how to organize your billing so that the burden on you is minimal. But I wouldn't start trying to be punitive about how much she charges for a half hour ($125 vs. $75) -- you're not the one paying for that, and she may well have a perfectly good reason to have adjusted her fees in that way.