You must have been driving like a grandma, totally flat area, a tailwind, a/c off, no passengers, no cargo, a sail on the roof, and over inflated tires.Yours is not legit.
Below's what I snapped after pulling into my driveway from recent 200-mile or so trip.
True.Never trust the EVIC MPG reading. It will probably be 1-2 mpg off the actual calculation you can do at the pump when you fill it up.
I was able to get 18.5mpg on my 2011 Ram Hemi while pulling a 2000lb tent trailer and 2 mountain bikes. This was on a 300 mile trip to Palo Duro Canyon, TX.