As to why Ford "recommends" a premium fuel, do you know anything about marketing?
I agree that it's part of their marketing program to say you can run 87, since lots of people are too cheap to buy premium, even after spending $70k on a truck. But the reality is that's not the right fuel for the truck.
Per Ford:
"Your vehicle is designed to operate on regular unleaded gasoline with a minimum pump (R+M)/2 octane rating of 87 or regular unleaded gasoline blended with a maximum of 85% ethanol (E85). Some fuel stations, particularly those in high altitude areas, offer fuels posted as regular unleaded gasoline with an octane rating below 87. We do not recommend
these fuels.
For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended. The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer.
Ford does not say the truck was designed to run on 87 and specifically states performance will be higher with higher grade fuel.
There is simply no debate on this.
Source:
http://www.fordservicecontent.com/F...s-Manual-version-2_om_EN-US-EN-CA_12_2016.pdf
See page 177.