I couldn't agree more. I work at a John Deere dealership and have learned over the years the OEM's know what they're talking aboutAs I'm sure @P. A. Schilke will join this in time he will have good input in this.
My thoughts are simple. Ford knows what they are doing. If thier oil wasnt up to snuff they wouldnt have it. If it calls for Synthetic blend(thier particular formula) as a minimum then run it. If you want to run Full Synthetic then run the Ford Full Synthetic.
Ford already states that Full Synthetic is not required unless you are in extreme cold climate(-20°F).
Will running a differnt oil ruin the engine? Well if it does not meet Fords specifications then it is possible but then again hiw do you know if the oil meets Fords specifications?
With that said just run the Ford Motocraft Oil.
Lol with that said I would not go to that dealership. Why you ask? Well they more ormless are refusing to use Fords stuff.From my dealers Service manager- they no longer use Ford synthetic blend, they have discovered that there is no rule stating how much synthetic oil has to be in the blend that allows it or any other Synthetic blend to label it as such , so they have switched to using Valvoline full synthetic, unless the customer specifically asks for the synthetic blend.
It's not like food or over the counter meds etc that have to label the percentages of products in most cases. Kinda like drinks that have fruit flavors, read the fine print most say contains no fruit juice.