I just got a 2013 Pro4x and it only takes about 16.5-17 gallons after the light comes on. I also thought that to be strange.

I am considering driving it for a while with the light on to see how far it can go...I would think that I should be able to burn at least 3 more gallons. At the 15-16mpg I have been getting that would be another 45+ miles after the light is on.