Before, I have been using Shell Rotella 15W40 Diesel oil because of its high zinc content. I was reading on another thread, that now even this oil has lower zinc phosphate content. The one I was getting before had the CI-4 rating, the ones in the store now have the CJ-4 rating.
I found some other diesel oil, 15W40 with CH-4 and CI-4 ratings. I don't know who makes them, as they are packaged under the stores own brand.
Anyone know if all CH-4 or CI-4 rated diesel oils would have a higher zinc phosphate content?

Fleet Farm it is packaged by Citgo. It states this right on their label. If it isn't on the label ask the store that has the oil they should know who packages it.