Oh, no doubt. I am 100% positive if I had your rig for the HT, I'd be pushing it further, and more often.
For instance, after I implemented room treatments, I could further push the volume further before discernible room issues became overwhelming (I know they still do, but that point is now further away).
After I implemented Audyssey XT, I could yet push it further. It was after all that when I could even get to -7.5 to begin with. Before, I couldn't even get to single digits without it sounding pretty bad.
Obviously, it's not just about volume only, but the quality of it. I know you agree. Bastard.