yes, the MACs are conservatively rated. for all practical purposes, and they are overbuilt since they were designed to put out that power level all day long....not many amps will do that.
25-40 watts is not much different in power. What is different is the sound of the tube 6L6GC vs. 7591, and sand rectifier vs. glass for the '30.
I had a pair of MC75s and MC60s, basically the same amp; but one has tube rectifiers, the other has sand....the tube rectifiers to me do sound a bit more musical....so sold off the 75s and bought another pair of MC60s....
and I know this is sacred ground for some, but the MACs can be scary good if you replace those bumble bees with some Jensen copper foil caps. very organic type sound, and tremendous hold your butt in the listening chair power.....