Everything you're talking about is frequency dependent.
most output - at what frequency? Maybe I wanted the most output at 20hz. If I wanted my peak frequency to be at 45-50hz, maybe I would throw it in 1 cube sealed, like eclipse recommends, and how I had the sub running.
Do you know why the recommendations are the way they are? Because that is what gives the response curve a semi-"flat" nature with a peak in the middle. This peak creates the illusion to the consumer that their subs are LOUD and can POUND.