I see what you mean now.I thought one would be wise to keep inside the 80% performance. Admittedly, only something I've read.
Nobody should run it at 100%, indeed. But they (quality units) CAN output 100% of spec'd value. Often people subtract the efficiency rating from the output, which is what I though you were trying to convey. Canned systems like that have enough power to run what's in them, but typically not much more. A fair warning!
Anyway, thanks for sharing!