That is just one number after the decimal being displayed. The internal calcs use more precision. There is, however, rounding going on somewhere. The GH hybrid has my lifetime MPG close to 0.2 MPG higher than actual, based on my calculations -- even though I provide the same data of miles driven with 0.1 mile accuracy (that increases with miles driven), and gallons used with 0.xxx accuracy. In my specific case, the total miles driven now has an accuracy of 0.1 * 20,000; and each tank's gasoline is recorded at the pump to 3 significat digits, so overall accuracy should be three significant digits.

This has come up before, btw, when Jason was trying to get a handle of the DB's accuracy. I cannot remember details, but Jason found an error in the code that he fixed.

R2-E2, 2G Prius.
Highway/City/Husband/Wife MPG: 56.5, as of 12/2005, 26K miles

Jac Nasser, Ford President: "We are planning to launch a hybrid version of
this car [P2000] within this year [1998]. We will also make FCEV available in
2004."