He does recommend AF fine tune if a consistent issue is shown, but I think he's a bit more extreme in his expectations that live view and AF should match exactly. AF is not precise. One can argue how imprecise it is, but I think everyone will recommend you do this many times on different subjects and look for a pattern, not a single bad case and stop. And bear in mind edge sharpness is naturally lower on many lenses, hence the live view comparison.
For me, I took a garage door, set up a tripod in front of the center at about 30' with a 14-24 lens (optically one of the best), three focus charts affixed in each focus point so I didn't have to move the camera, and did a bunch of testing.
The problem shows up by the left being dramatically different from the right. On my repaired camera, the left and right are similar, but significantly different from the center on some lenses, and about the same as the center on others. It will never be perfect, but the repair made it good enough that now I can use the left/right in portraits at F1.4 and not have one be worse than the other.