Consumption & AVG MPH Display

True except we're talking about speed not consumption. Your points are all valid except that I think that where average speed is concerned, a common-sense approach would be that average speed = average speed while the vehicle is in motion. Average consumption should take into account time spent in Park, I do agree on that.

Now, if you wanted to compromise and say that average MPH should be calculating when the ICE is on and/or the car is in motion, I suppose that's fair. But either way the measure here is the average speed of the vehicle independent of consumption.

 

You may be on to something there I don't know

 

When I first read the manual for my Prius, I also wondered if the CONS is somehow tied to the 1 minute and 5 minute calculations. It is not. That is different screen. You can think of the CONS as your MPG since you reset the trip odometer. For CONS (mpg), you do not have to worry about the READY detail. Typically, the engine will be off when not moving, so it should not affect your CONS mpg.
As many others do, I reset the Trip A every time I fill up with gas, and use it for the miles in the true MPG calculation (miles traveled / gallons to fill). I reset the Trip B frequently to learn the intricacies of the Prius.

My stats, on flat land in Miami, but with full AC:
In the first 2500 miles, I have figured out, mainly by resetting Trip B many times, that:
First 3 to 5 miles (5 - 10 minutes) are much lower gas mileage than after car warms up (maybe 35 mpg for a very short trip of 3 miles or less).
Easy to get 55-60 mpg per the CONS number after warm-up in rush hour expressway traffic from 10 to 55 mph, occasional total stops.
Steady 65 mph is about 50+ mpg per CONS, 62 is about 55 mpg. 75 mph is about 47 mpg or so. etc. (with AC on)
I am always slightly disappointed at fill-up time. My real mpg has been 1-3 mpg less than the CONS reading on my Trip A, every time.
Each tank full my MPG is creeping up. Not sure if I am staying out of red zone more (learning to get more mileage), or the car is breaking in. With all the short trips tied in, I get about 50 mpg real mileage, 52 mpg CONS per fill-up. But that includes some experimenting still (Comparing a 25 mile rush hr expressway trip to work driving aggressively, leaving no space to build in front, zooming in and out, resulting in ~ 5-10 mpg less than very conservative but pleasant driving without entering the red zone unless needed for a merge.

 

My CONS mpg very closely matches your stats while driving in IL and WI (mostly flat, also). I also find that after averaging 50 on the CONS display I will calculate about 48 at the pump. With about 6000 miles driven, I now see my MPG slightly worse as colder weather arrives and I use the seat heaters and cabin heating.