At least, in regards to commercial heavy engines, the OEM's are not nearly as goofy about oil selection as the auto/pickup OEM's. Fleets are not going to stock a bunch of different classification of oils and different viscosities. The newer engines that will have FA-4 recommendation, I have seen OEM stuff that says they will allow CK-4 to also be used. And while the OEM's have been factory filling with 10w30 for quite a while. they have no issues with 15w40 use by owners. The "certification" game seems mostly prevalent in the smaller auto/pickup market and worried about by owners of such vehicles. The commercial crowd doesn't fret so much over the cert issue and there are hundreds of thousands of heavy commercial engines that see over 1 million miles on them before major engine work.
Commercial truck OEM's are not as focused on trying to void warranties over trivial stuff like this. If the auto/pickup OEM's would follow that lead a little better, they might have a better reputation and more loyal consumer base.