Randy(and Charlie), as Rick mentioned, the setting of the level control on the sub(or a receiver too, for that matter)doesn't indicate what percentage of the available power is being used. It simply sets the desired sound level during calibration, in coordination with the sub output level setting on the receiver. Loudness is loudness, and an identical amount of power from the sub amp is being used, regardless of where a control setting happens to be. A given level can be reached either with a high setting on the receiver and a low setting on the sub or vice-versa. It generally doesn't make any difference which way it is(again, the exact same amount of power from the sub amp is being output), except on a sub with auto-on, a too low setting on the receiver might not output enough voltage to keep the sub amp "awake". On the other hand, some receiver sub outputs distort if set too high(e.g. above 0); so the general idea is to not have either control near one of their extremes, but otherwise don't worry about it.
