This is for my 17 EL Limited. 15k on the motor at the time and 5200 miles on the oil sample. Oil used was Castrol Magnatec. My truck has been tuned for the bulk of that 5200 miles and Ive towed my toy hauler loaded to the max (9000lbs) multiple times on that oil. So the motor has done some work. When I sent in the sample I told them I wasn't interested in extended oil change intervals so that's why there is no mention of that. I plan to stick to around 5k oil change intervals. With that said and the results from this report I figure I could go a lot longer on the oil. Also the lack of fuel dilution is a very good sign. Blackstone seems to think the motor is in great shape.