It's not unheard of for Ford to back-spec cars for 5W-30 that were originally specced for 5W-20.
I'm one of those thick oil(within reason) guys and have one car where I more or less run Maple Syrup(20W-50)...albeit that's the factory specified weight for it.
I bought my MKZ(Fusion by another name) from my dad with a bit over 30K on the clock, and had done the previous few oil changes on it for him. It started getting Mobil 1 5W-30 at around 20K miles(BTW, he bought it from my grandfather with 17K on it, and my grandfather bought it new). It will tick over to 50K in the next few weeks, and I'm continuing to run 5W-30 in it...in fact in my ownership I've stepped up to 10K OCIs so an oil change is on the table sooner rather than later.
I waited a bit longer in my old LS to jump on the thick oil bandwagon, and didn't go to 5W-30 M1 until about 120K miles(it met an untimely demise, albeit with the drive train in perfect condition, at a bit over 150K miles). I had switched to using M1 "High Mileage" 5W-20 at around 80K, and at that point was also doing 10K OCIs on M1. I bought that car with 50K miles on it, and my first few OCIs were with Motorcraft 5W-20 at 5K. Had it not been for a blown passenger side airbag, I'd most likely have fixed the car and would still be driving it(aside from my fear of the driver airbag going, the blown pre-tensioner that made the driver belt only fit me, and the broken windshield the only thing keeping it from actually being drivable was a $20 cracked thermostat housing that would cause it to lose its coolant when the system was up to temperature and pressurized)-and likely still going strong now at 160-170K on 5W-30. I sold it to someone who planned to fix it, although I haven't asked about his progress.
