Just a reminder that UOA results DO NOT reflect engine wear rates. Not even close. In fact, no information can be gathered from normal UOA results with regard to engine longevity. I understand there is a culture of belief with regard to "wear metals" shown in UOA results.
I worked with Mobil Oil engineers on 2 projects, SHC 100 grease, and Mobil Jet 254 high thermal stability turbine engine oil. My job was to remove parts and transport them to the Mobil Oil engineers. I learned very quickly about UOA results (as we did performed them constantly. The wear rates were measured by scanning electron microscope. There was no, as in ZERO correlation.
Let's be honest about this. An Fe of 50ppm would indicate high rates of wear when contrasted to 8ppm Fe. Yet, the engine with 50 is very likely to have visible hone marks in the cylinders at 300,000 miles if maintained well. The idea that the iron comes from the cylinder walls is nonsense.