Dexos1 and Dexos2 (which is a GM thing) licensed oil exceed the GF-6A and SN+/SP standards/service categories. If anything, with using a "mix" (I don't consider it a mix) like this you consider the lowest rating, but it is still well suited for whatever year and engine you have if it has a 0w20 oil recommendation.
That ford requirement is for GF-6 0w20.