I hope we agree If you see TO-1 or TO-2 on your EICAS you are using fixed derates and those should not be exceeded
I believe I did say you can move the thrust levers forward for Assumed temperature however with the combination of fixed derate and ATM reduction its not recommended as there is no indication of when you have passed the fixed derate limit. Thats what I meant by "beyond assumed temp limit"
Yes full power with ATM only then move as you wish