What results do you not understand? Did you look at the table relating SPL to known sounds below?
I think THX says to provide 105 dB/spkr peak SPL at the listening position. Personally, while my system will do that, I do not want to be in the room. 100 dB is probably not an unreasonable target for peak SPL. I listen much quieter, probably 70 - 80 dB, as it's loud enough for me and I need my ears.
Another useful couple of factoids is that a 3 dB increase in SPL sounds to most of us like a small bump in volume ("turn it up just a hair") and requires twice the power to the speakers. Boosting by 10 dB sounds twice as loud and require ten times the power. It takes a lot more power to make a sonic (audible) difference.
In any event you should try with your AVR first before deciding you need more power. Some do, but my impression is that most folk buying power amps would be better served spending the money on movies and music.
IMO - Don
"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley