You 2 arguing about labels and descriptions have made my day.
Neither one of you is wrong. Since I'm active duty, I've been able to travel all over and you'd be surprised at what the gas stations have labeled and for what.
"Plus" is a thing, so is 89. If you don't know what mid-grade fuel is by the time you're of driving age in your local, you may not want to drive. I can look at any pump and make an informed decision on what each gas is. Doesn't matter if it's Silver, Plus or 89. Everyone has labels for a reason. The manual has "plus" listed because "plus" being labeled at a gas station over simply saying 87, 89, 93 on the big sign is a thing and they accounted for it.
To be fair. I have NEVER seen "Plus" listed as anything other than 89 grade, but that also depends on the vendor of the gas (Exon for example) typically when you see "Plus" from one company, it's the same throughout the country in the United States at least.
Using numbers or labels may be a little easier to navigate to you than others and vice versa, and that is why usually 'both' are on the pumps and FCA decided to accommodate it in the manual because it is listed like that universally to most of their market. If they wanted to make everyone happy, they would also list Bronze/Silver since that's something I see at select gas stations.
Also, most likely we are truck/vehicle enthusiasts or we wouldn't be here, right? I have 3 older sisters. Growing up, we always had to tell them to get "Plus or Premium" and never used the actual octane numbers because they had no idea what that meant, hell, I suspect a lot of people have no idea what they actually mean and go off the label. The labels do coincide with the regions you live in.
Again, neither one of you are wrong, you guys blew this way out of proportion for no reason at all. Also to be fair, I also remember growing up and us having to put premium in our vehicle, my dad would just say "Get premium" and some gas stations had it, some didn't. Some did have "Premium" listed and the octane was different.
But that is all they offered. I want to say that these types of instances are very far and few in between though.