Caveat: Way too many hrs on 757/767 (15K)
But looking at this picture (identical one for a/c with EPR switch), it seems that only the A/T arm switch ON switch is required. CONFIG WARNING takes care of Flaps being in t/o range. I have had a situation where we pushed the button and nothing happended. Took a good look around, no warnings, cautions or Status msg. A/T arm switch Off and off we went with a manual throttle. Busy day, but if the TMSP is ok, that helps.