I went ahead and changed this at almost 8,700 miles because the OLM was at 10%. I was pleased with the wear metals, but kinda disappointed in the TBN, meaning the oil is essentially done. This was the first run on PU, which is now repeated for the new change. The first change was on unknown Ford dealer oil. Is there a chance that subsequent changes of PU will help the TBN hold on longer? Based on other things I've read about iron levels, calcium, and anti-wear additives, it looks like I should be able to go longer. Thanks! Fusion Oil Report 6/1/2014