Just a thought.
But on the boeing i fly, granted it is quite an old one (737-200, SP177 autopilot), on take off, u press the toga and once you get the throttle hold at circa 63 kts, it does'nt matter if you press the toga again. The throttles are in effect, in arm mode, where u can move them manually, but they will not move automatically. The throttles can be repositioned to any thrust setting, but only when u have throttle hold annunication. It is in effect the same as doing a level change descent. The throttles come back to idle, then they go into arm mode and u can set them wherever u want.
On a go around however, u press toga and u get x amount of thrust, press toga a second time and u get max go around thrust.
It may be different on this type, age of the aircraft and the engines being set by epr's, which must be set by 60 kts.
But as i said, just a thought.
Speedbird.