Ruby,
In your Power Stroke there is not one dino API approved CH/CI/CI+ oil on the market that will not work for 3K severe or 5K normal oil changes in your PSD. Pick one on price, color of the jug, or any other criteria you deem appropriate.
In my 95 PSD I have used Shell Rotella T, Delvac 1300S, Delo 400, Schaeffers, Amsoil, Royal Purple and also a 50/50 mix of Delvac 1300S and Delvac I. I have used oil analysis on all the above except the Shell and my mix of Delvac. You know what, they all worked great with great used oil analysis.
In my 01 PSD I have used Shell Rotella T, Schaeffers, Royal Purple and a 50/50 mix of Delvac 1300S and Delvac I (Mobil I Truck/Suv). I am presently using Schaeffers 15W40. Again, they all worked great with outstanding used oil analysis.
So my advice is to pick one and sleep easier. As mentioned above, Delo 400, Delvac 1300S or Shell Rotella T are all great dinos. Castrol has a 15W40 that I will try next. The specs looked good. I will do a VOA. But we are looking at the end of the year for this.
So in summary, if the jug says CI+ and you like the price and the oil has good availability, go for it. You absolutely will not go wrong.