Not all versions of Audyssey are created equal. http://www.audyssey.com/audio-technology/multeq
Not the same thing. Audyssey does 6-8 positions for the same seating position. MCACC does 1 position for up to 6 seating positions.
If I understand you correctly, I think it would be more intelligible as
Audyssey does 6-8 measurements from different locations to optimize one seating position. MCACC does 1 measurement each for up to 6 seating positions.
But that does kind of beg the question about how far apart the positions can/should be, or how MCACC manages to optimize the listening experience in so many different places at once. Magic?
Point being, this is some heavy duty science and technology, but at its heart, choices and compromises are being made by each system. Personally, I'm pretty happy with Audyssey but I can't really do much with my room. I think any of these systems should be a last resort, WAY down the list from speaker placement and room treatments. We spend a lot of money on components, recordings and speakers to hear "what really happened" and - no matter how smart they are - these systems necessarily make changes to what can otherwise be a pretty pure path.
And, you know, tone controls still exist, right?