All good points. I guess we just need to agree on a starting point so everyone is on the level.
On another forum some people give me grief for using the cars internal mpg meter for measuring mpg. One thing everyone can agree is that its right within 2-3 mpg. Well, thats great in my opinion. Otherwise to get your accurate mpg is a real fustercluck. Many gas tanks use a bladder that monkey around with the total capacity. Many gas stations have uneven parking lots so the fuel level may vary depending on pump used. Fuel or any liquid changes in volume based on temperature, so you may buy 10 gallons on a 100 degree day, but the next morning when its 60 degrees you got 9.3 gallons in your tank.
Then you got the mpge. If I am buying 10%e and 90% gas, how should I log that?