I went from the AEL to the HDH this time to see how the new Signature Series would work out. Not sure why my TAN is so high and the rest look good. This sample was taken right after getting home from a 9 hr trip back from PA. Air filter was changed at beginning of this oil run and the oil filter is the AC Delco. Diesel used was mainly from Sheetz which there isn't anything on the pump that states it has Biodiesel in it, just that it is 40 cetane. Averaging 45.7 mpg and it regens about once every 600 miles.