Common sense sometimes has to be used as well as following specifications.
I used to own a Corvair, and I made it a point to use AD ashless dispersant aircraft oil exclusively. These oils are not SAE rated nor recommended for automotive use. However, for decades, the Chevy Power manual recommended and advised the use of AD aircraft oil in Chevrolet racing engines (it no longer does), and dozens of other Corvair owners had found that it gave the best results in terms of not forming deposits inside the combustion chamber that would cause preignition. Many Harley bikers used it as well with equally good results. So I ran it in my Corvairs exclusively for a long time without problems. But I also changed my oil on time, every time.
The point is, the combined experience of a lot of technically smart do-it-yourself hands-on people is SOMETIMES better than the recommendations of oil or engine vendors. But if you are wrong, you have no one but yourself to blame.