I remember reading an article couple years ago that said something like Castrol did test their EP oil on a 3.5 Ecoboost. That basically means Castrol was able to get the Ford WSS-MC***** oil spec certification.
What Castrol is really saying is their oil tested good enough and within the limits of all the API's series of industry standard oil tests on the F150 engines, (I'm pretty sure Castrol specifically tested it on the 3.5 Ecoboost engine).
In my book, any API SP certified oil will work great on any Direct injection Turbo engines if you follow the recommended or the "logical" oil change intervals.