I ran the MACC setup with the Microphone if that is what you mean yes. So with the volume starting at -100 to listen to music at a volume just a touch above speaking volume it rides around -30. That means from -100 -90 -80 -70 -60 -50 -40 to -30 all used up. All that is left is -20 -10. About 1/4 of the volume range.
So, the 33 goes down to -100 dB? Interesting. 0 dB is no sound at all, so perhaps their 0 dB reference is 100 dB these days. That would surprise me, as THX reference level is 85 dB average. My VSX-23 goes down to -80 dB, so I'm guessing my 0 dB reference is 80 dB.
Anyway, a bit of information on how dB relate to power. To increase sound by 10 dB (quoted by some as being twice as loud) takes ten times the power. So, going from -30 dB to 0 dB on your volume scale is 1000 times more power to be eight times as loud. If the 120 W RMS rating is at reference volume, that means that you're using on the order of 0.1 W when listening at a touch above speaking volume. That's in line with a lot of what I've read in the past. Speakers are often rated at between 80-90 dB at 1 meter away when 1 W is put through them. (But to go up 10 dB would take 100 W).
How does your system sound when you turn the volume up more?
EDIT: I just read your edit, and I see that your reference is older systems. In the past (at least my receivers back in the 80s and 90s), the volume knob wasn't relative to some reference level (because they didn't use to have microphones that could measure how loud a system was and digitally adjust the control). From what I was told back then, a lot of those systems were pretty much maxed out in power at about halfway around the dial, so perhaps it's just a matter of getting used to the new approach.