Consumption Graph - Is this Normal?

Just bought 2013 Prius Persona SE (Black Cherry Pearl); low miles; Toyota Certified Used Car. I also have 2010 Prius Four with Solar Roof and Nav.

The Persona has Nav and an approx. 6" screen where I can click the "Car" button on the radio area and see a screen called "Consumption" which is either confusing me or not working correctly. Don't confuse this screen with either the vertical arc-like meter or the oval-like information area at the top frontmost of the dash.

I am very used to my 2010 model but it does not have the "Consumption" screen.

OBSERVATIONS:
The "Consumption" window has vertical bars in one-minute increments which seem to be at 100 mpg over the course of a trip. I mean at 100 mpg A LOT! A recent 15 minute trip where I left my neighborhood going up a 150-yard hill onto an essentially flat road for maybe eight miles (there was a slight descent of maybe 150 feet downward over those 8 miles) had the consumption screen pegged at 100 mpg for almost the entire trip. The frontmost oval-like consumption display mimicked the consumption screen. When I arrived and turned of the motor, the trip telemetry said 68.5 MPG (the info at left frontmost part of information area—not consumption area).

The blue "Consumption" display uses an "E" which equals 30Wh. There were maybe two (total) of those "E" characters displayed at bottom of vertical graphs for this trip.

Similar behavior occurs when I'm driving in mountainous country. There's no congruity with seeing 100 mpg consumption and the final trip average mileage, far as I can see.

The end of trip (turning off engine) display always seems to make sense, ranging from 29 mpg to the 68 mpg depending how I drove and the stop/go and elevation parameters. Overall gas consumption seems normal (ignoring all telemetry displays other than fuel gauge). I'm still on my first tank of gas so have not done the odometer miles / fill-up gallons math but I expect normal consumption overall.

QUESTION:
What is going on? Can someone talk me down? Is my "Consumption" display giving me normal values or is it buggered?

Thanks to you all.

PS. I simply love this Persona.

 

Focusing on "consumption" graph only as outlined in original post, graph is similar whether warm or cold car.

 

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