health insurance

I have Medicare & Medicaid. My psychiatrist wants me to undergo a 30+ visit, Transcranial Magnetic Stimulation next year. Does that mean 30+ co-pays or like one hospital procedure?

If a person reaches their OOPM on a claim, but the medical facility gives them a discount on the amount due, can the person’s insurance company change any EOB’s that came after that claim that were $0 cost share until the person reaches the OOPM from the discounted amount paid?