We got a customer UOA back from Wix yesterday and everything looked great except for the iron level which was 55 ppm. This seems a little high to me but Wix said it was within spec and there was nothing to be concerned about. In looking at some of the other UOA's for the 7.3, it seems that they tend to shed more iron with Rotella than most other oils. This truck is bone stock, almost all the miles are long trip, highway miles pulling a trailer and he always changes oil around 7000. Is there an issue with 7.3 Powerstrokes shedding iron with Rotella or I am reading too much into 55ppm @ 7000 miles? Thanks for the input.