Schmacko, that's only true if you have a fixed pitch prop set to the correct pitch. With a constant speed prop you can reach max RPMs (full fine) with only, what, 10% power?
Anyway, let's not call 'em power checks but run-up checks, follow POH guidelines and be done with it.
Tegwin, for fixed wing light aircraft it is common to do the run-up checks at the hold, so that other aircraft are not blown away by the prop wash. Plus, on long taxis you might foul the plugs if you don't lean properly while taxiing. But doing these checks at the hold means that you might be holding up the aircraft behind you, so you might hear the occasional communication about this. ("G-XXXX, ready for departure? Negative, not finished the power checks yet, G-XXXX.") For helicopters the situation might be different since you do them before and when you lift into the hover.
At the end of the day, the checks are more or less the same for piston fixed wing and fixed rotary: mags, carb heat, t&p, idle. In the fixed-wing world we also do a full & free check of the controls, which gets kinda interesting and expensive in a helicopter once the blades are spinning. And there's a little variation because fixed wing either means fixed pitch (throttle impacts rpm directly) or constant speed (throttle increases power, which increases rpm, which prompts the prop to get more course, reducing rpm), but in a heli you're using a governor (collective increases pitch, which increases drag, which decreases rpm, which prompts the throttle to open, increasing rpms again). That might make a little difference in the procedure for the mag check.