Wondering if doctors take the authority and discretion to say when you are done with adderall?

Doctors can do whatever they want. No I have never had any meds pulled. If they get any ideas that you are abusing or selling your meds, they will cut you off ina heartbeat, that's what I know.

also if their effecting your blood pressure they will take you off them

I doubt they'd arbitrarily pull you off a med because they got a bee in their bonnet.

How the med is affecting you or whether they feel you're abusing the med would be more likely.

I would however strongly encourage the doctor to disclose the reason behind it since you are the one that will be affected by the withdrawal effects.