I had this surgery. That dropping of 10 mg testing or not seems extreme and dangerous. I came home from my surgery on 20 mg and over many months decreased to 15. I was very weak in the mornings and now take 17.5mg. Yes 2.5 mg made a wonderful difference in me. How long must she wait? And did they take the whole gland out along with the tumor? If she has some gland she may do better. But check in with the doc and watch her. She could go into crisis (plummeting blood pressure). Good luck!!