I recently posted a blog in regards to my fuel mileage results as figured on paper for 35,000 miles. The engine reports are mirroring my on paper calculations very closely. The only time I've noticed a variance between my paper figures and my ECM reports are when I use the heat from the ParkSmart HVAC system. The fuel used by the heater doesn't show up on the engine report. Using the heat has only changed the figure by 4 to 8 gallons in a week.  While the last report was for 35,000 miles, my DDEC Report is for the last 13,805 of those miles. Important figures to note: fuel economy at (9.24)  driving economy (9.31) E-Coast time (23 hours, 31 minutes, 7 seconds or 9.59% of operating time). DEF Economy (338.90 mpg) .