Sienna LE 2008 . . . Accuracy of fuel consumption display?

[dawziecat]

I read elsewhere that the figures displayed by the computer display are not accurate?

I tried a search here but found no information.

I just traded my '06 Sienna LE in on an '08. Seemed to me that the consumption figure displayed on the '06 was accurate. At least, after keeping figures manually for several months, I gave it up. The computer figure was so close to my long term average as kept by hand that it seemed pointless to continue the exercise. Of course there is a large variation tank-to-tank when measuring manually as one is never quite sure just how "full" one gets the tank from fill up to fill up.

I thought the computer was likely MORE accurate than my own figures for that reason.

The '06 had a display of 9.9 l/100km when I traded it in. It settled in to that figure after a few months and never varied after that. The '08 displayed

12.3 l/100km when I accepted delivery but has already settled in to 9.6 l/100km. It reached that figure after about only 400 km on the odometer and has changed

no further since. It presently has about 1100 km on it. (For the benefit of US residents, 9.6 l/100 km is about 24 miles per US gallon.)

Does anyone have any information as the fundamental accuracy of the fuel consumption figure displayed by this Toyota device?