Ovarian Suppression to Use AI's (unsure of menopausal status)

My wife will soon be starting the next phase of her treatment plan. Because of her low PR (5%), but high ER (90%), both oncologists are recommending using AI's instead of Tamoxifen.

One of the oncologists had my wife take a blood test to determine if she is in menopause. Her estrogen, FSH and LH levels all came back suggesting menopause (but maybe its just perimenopause?). However, I have read that these readings can fluctuate and that a single test may not be accurate. I believe it is important to know if she is in menopause to ensure that the AI drugs are working properly.

Are there other more reliable tests, other than a blood test, to determine the menopausal stage? I know not having a period for 12 months is a factor, but she was on birth control until May and didn't have periods before then. When taken off after the BC diagnosis, she had some but nothing regular.

If the blood test is the appropriate test, is there a recommended testing interval to determine if the results are accurate?

If one is unsure of the menopausal status, do you normally have ovarian suppression done anyway? If so, are there any risks or downsides of doing this if you are, in fact, in menopause (but are not certain of it)?

Thanks for any information you can provide.