I don't remember seeing any such measurements. It will be a complicated thing to do because it would depend on the magnitude of the cuts and boosts applied. You just bring up any point about how silly it is for the believers (and those who believe them) who thought they heard night and day difference between brands even if pure direct mode at low level listening, yet they would use their favorite REQ that obviously would have affected THD+N a lot more than the -70 dB vs -95 dB THD+N due to the brand's design, build and implementation. For those people, it really shouldn't matter if THD+N is 10% or 0.001% (okay I may be exaggerating a little
). All it matters could be to give them the REQ that they trust. To some, you can probably give them a fake REQ, say with a Trinnov UI, but in the background it would run Audyssey, or just some sort of tone control lol, and they would still use all sorts of adjectives to describe the superior sound quality they thought they had..
That being said, I am still disappointed with Yamaha's repeat inconsistent performance on THD+N that Gene discovered when measuring the A6A or was it the A8A? Totally not an audible thing I presume as Gene didn't even mentioned/showed it in his follow up video, but it made me wonder what's going on with their engineering and quality control departments.