I think the best way to get a gas mileage figure is to take the average of several fill-ups. Wife and I just went 549.2 miles. I start at full, as close as I can with gas tank restraints. I start with both trips meters set to zero. I use "A" as total trip meter and "B" as point to point meter. It only takes a min longer at each fill-up to reset "B" to zero and note on receipt mileage from last stop as a back up in case you clear the "A" trip meter accidentally. (I erased "A" from an earlier trip :banghead: but I can now recreate total mileage from that trip if I want:yes:.) As a back up you might want to note total trip "A" on each receipt also. At end of trip add gallons and divide into total miles. In our case 549.2/18.698 = 29.37 Close to 5000 rpm's seemed when I got best mileage. 55 mph in 4th gear and 70 in 5th. 2013 RTS This basically takes the need to be precise at each fill-up out of the equation.