I'm with Shawn, using one spot could be detrimental to other listening spots.
While I don't have an "auto" EQ function on my AVR-3803, I don't think that they can be very accurate. This is my opinion so don't flame me, as I'm not saying it can't make it sound different for the better. There's been some posts on this issue and while helping one frequency, it can alter another that was more accurate to begin with.
So it could be more beneficial if one frequency that's very inaccurate in the room, is a highly audible frequency so that the inaccuracies made to other frequencies are not as substantial as the benefit to that one frequency. Of course, this could go just the opposite if that one inaccurate frequency isn't audible, being it's very low, very high or masked by other frequencies most of the time.
So even if the accuracy could be questionable, it may tailor the music in a way that sounds better to the owner. This is obviously the case as many have said they like the after effect.
Now here is the big "BUT". But, if these auto eq adjustments are just made at one listening spot, they could easily had made the frequency response much worse at another spot. For this reason, I feel Denon 'originally' had the right thought by wanting multiple mics. Unfortunately they gave in to the competition and went with only one.
However, if you could note the auto measurements made at different spots, you could then average them out so the sound is best at all spots. This is important when you have more than one person enjoying music or a movie, as I often do.
For me, I don't alter anything as I'm a purist. I want the signal as it is with no electronic monkeying around, except for maybe some up-sampling and 24 bit interpolation.
Have a good one.