Well that's utterly useless. All that hassle for no change (now) or slightly worse performance (older models).
I second the tips about reducing background noise, esp low freq rumble (fridge for instance), and having a try at limiting correction to between 300 and 500 Hz.
Lastly anecdotal: my Denon AVR's included Audyssey mic was actually faulty, which I only noticed upon remeasuring after shifting speakers. I was playing around because the sound (with correction) did not sound ok to me. The app would repeat a channel's sweep at ever higher levels and reported it could not detect it. Actually it went so loud I feared it would damage the speaker, so I quickly turned off the whole AVR.
Testing the mic via a laptop taught me its cable was broken inside, slight movements would cause distortion or no signal at all. I then used the old mic (same model number 100% match) of the Onkyo AVR I had replaced. Much better results, obviously.