Congrats! I can tell your system must be sounding really great with little distortions. I know that because at volume 80 you are getting close to THX reference, may be 2-3 dB short because of mic tolerances and everything else may not be totally accurate. In general, people don't perceive it "loud" even if it really is loud, when sound quality is great. Conversely, if it doesn't sound good, you would perceive it as louder than it really is.
Do me a favor, set volume to 80, and measure the spl from you main mic position with a meter, use C weighting, response set to slow.