I think you need to give the display a little more time to show amore accuracy. I've had my (decked out), CG Lariat for just over a month now, and am only on my 2nd tank with about 425 miles on it. Right now, the display shows 24.3 mpg. It originally showed fairly low mpg and has increased...
Same here, including year and diesel. Manual transmission (I think a 5-speed?). My 1st 'new' vehicle. Bought it for the mileage and cheaper fuel prices. Diesel was less than gasoline at that time ($0.89/gal. -here in PA). Diesel started rising past gas within a couple years after buying it...
One local dealer to me, had about a half dozen advertised. One was almost identical to the loaded 24 Lariat EB I have on order, right down to the color. Price was about $150 less due to very minor option differences. Gave them a call to let then know I wanted to see it, drive it, and buy it...