I don't understand the "screw the math" notion. If you were to screw the math, physics, and science, you wouldn't have an amp, source, or speaker in the first place..
At low volumes, with a well designed amp(HK does have slightly higher distortion itno 4 ohms than a usual amp, around 0.2% - and the wattage barely increases, which could indicate slight problems with a 4 ohm load, which could be why it doesn't sound as perfect as your rotels with a 4 ohm load), 50 watts and 500 watts won't matter because you're using such a small fraction of the 50 watt amp's full output power..
