MPG on MFD not resetting with fillup

I have a 2006 Prius that I bought a month ago. I've filled up twice since I drove it off the lot, and both times I've noticed something odd that I didn't notice with my 2005 Prius.

As you know, shortly after you fill up with some minimum amount (three gallons?) of gasoline, the number of miles on the Info MFD screen will reset to zero so you can measure the distance you drive on each tank. I *thought* that the MPG number also reset, but that's not what I'm seeing. Let me give you specifics...

On the first tank (the one the dealer put in the car for me) the MPG fluxuated quite a bit at first, then, toward the end of the tank it settled in at 43.6.

On the next tank, after I filled up the miles measurement reset from 363 back to 0, but the MPG stayed at 43.6. And during that whole second tank it hardly budged. It didn't fluxuate at all. It kind of slowly crept up to 43.9 over the whole tank, and was at 43.8 when I refilled again today.

Then when I refilled today the miles number dropped from 379 back to zero, but the MPG number stayed at 43.8 and didn't change at all on my drive from the gas station to work a couple miles away.

I really doubt that in those two miles I stayed almost perfectly at 43.8. Instead, it looks like it's keeping some sort of lifetime MPG.

Now, I know that I've read about other people getting really high MPG settings on their MFD on the drive between the gas station and their homes, so it would appear that the MPG value does reset for other people. Are you all hitting the reset button on the info screen when you fill up, or is my car just weird?

 

Ah, okay. I'm still learning some of the differences. If this had been my first Prius I probably never would have questioned it.