There's no need to act like a troll and bait people into an argument.
Look.....correct me if I'm wrong, but all makes/models are subjected to the federal government's MPG test with the accessories (options) that will get the maximum efficiency during said trials. High rear gearing, best tranny, best tires, etc.
In the end, the city/hwy rating is the AVERAGE of what the feds found during the tests. Yes, that means high and low performing vehicles. Let's face it: they may be mass produced, but they are HARDLY the same vehicle from one to the other. Castings, drag from bearings, poor tires....you name it. It's been that way since we started building automobiles.
Some items that cause lower MPG includes, but not limited to:
Type of tires used (I have Nexxans street design tires....does anybody else? (on a side query)).
Rear gearing (of course)
Size of tires
Calibration of fuel/air tuning
Cam lift and duration
Air efficiency in plenum
Head casting
Poor quality of spark plugs, and therefore poor flame travel in the combustion chambers
Any air drag (imperfect sealing or alignment of windows/doors/hood/etc)
Any physical drag (ex. poorly designed tires)
Gasoline purity
Hard driving (some may call their driving as 'soft', but in reality they are trying to keep up with the surrounding idiots in traffic)
Also:
Terrain (I live in mostly flat, florida land....but with a few rises and dips)
Rise in elevations on daily route
Humidity
Elevation (ex. Denver), which will give you more air (lower elevations) or less (higher).
Outside temperature
...and many others
I sympathize for all you who have lower-than-average of the feds city/hwy average. I had a POS Santa Fe that did the same thing. 2.0 Turbo engine that could never attain the 20/27 average they put up. Best ever for it was 19-22.5 ON THE HIGHWAY. Then, like many other Hyundai engines from that time period....it blew up all on its own. Hyundai replaced it (long story...just search for it if you want to read up about it), and the new engine could hit 20/25 for city/hwy. To tell you the truth, it seems the only way out of a poorly running Hemi (or any engine/car for that matter) is to just trade it back in. That's hard to swallow, yeah. I really doubt you will get it resolved through Chrysler.