Johnny, what you've described isn't anything unusual. If you're talking about pop music, much of it is recorded as loudly as possible, since it's believed that loud sells. A setting of -10 for movies is quite common. So, there's actually no "problem" to "narrow down". As long as you can get adequate volume on source materials, don't worry about what setting is used to get it.
As to the dialog in the center channel in movies, it often isn't recorded at a high enough level to be clearly understandable, and as CV mentioned, raising the center channel level a few dB in such cases can help.
