There's no harm in the numbers on the dial being higher, as long as the unit's output capability isn't being exceeded.

Likely, the input pads are differently. The problem with them being set lower is that you're running the preamp levels a bit lower, and, theoretically, the extra power amp "volume" that you're applying might have a bit more background noise.

::::::: No disrespect to Axiom, but my favorite woofer is my yellow lab :::::::