I did my own in game testing today and with Ranger-Sniper/Rocket and Wing Diver-Lance/Plasma Launcher did not see any increase in damage with more than one post shooting the poor Air Raider. I also mixed posts and the gun power boosts with no increase.
It is possible that stacking happens but only with certain weapons I guess...
So my question is does anyone have non-anecdotal ("man, it sure seemed like we did more damage...") proof that power posts stack or should someone delete that erroneous thread?
it's really easy to test if the power posts stacks - shoot your own vehicle, or a vehicle in split screen, with 1 or more power posts active. if OP has tested it and they don't stack, then they don't stack i guess.
anecdotally, i've been in sessions when people have put like 6 down, and it's not made it any perceivable amount better, but that's not really a proper test i suppose.