[JJ_SO]

...And because the AF misses are due to different wavelengths focusing differently, and lenses do not have the same aberrations over the whole focus range and even less so over the whole zoom range, AFMA is even less helpful.

    I'm not sure what world I live in ..... and I don't have any super optical technical knowledge ........ but you always come up with theories, (which could be technically right no doubt)  ..... that I struggle to align with my own experiences. 
Nikon has not a flawed system..... and as JoJu says ..... most of his lenses needed AFFT and the result is fine ...... so all I can conclude is these theories just don't apply themselves in any meaningful way to my shooting.
  If DSLRs didn't have AFFT I would have dumped them years ago!!
  --
 JoJu, the Tamron has trouble at 600mm@ F6.3 to achieve focus on the outer corner points (D500) .... this is normal ....... not great, but normal.

I would appreciate that you put quotes and author right - what you quoted was said by BC, not by me. I just quoted a part of his post, see here: https://forum.opticallimits.com/showthread.php?tid=4699&pid=50530#pid50530 last paragraph... I just don't know how to name the author when I quote a single sentence instead of getting longer and longer quote-packed posts. Anyway, I think I got what you wanted to say.

I don't say, the result of AF fine-tuning is fine or more reliable - the fine-tuning doesn't change much of the reliability, but if it hits the spot, it's a least not front- or back-focusing. Whereas proper focus with AFFT is, at least wide open, mots of the time a lucky guess with most lenses.

And it was not the 150-600, but the 100-400 is not faster at the long end than the 150-600. If you don't use the outer focus-points but one of the cross-types it gets more reliable. That's not because the lens is and, that's only because Nikon puts an artificial limit on most of the focus-points. IF aperture <f/5.6, THEN DON'T AF or however programmers will text it.