We are only averaging around 16. Mostly city driving but with winter gas in our area and tire pressures around 34 to 35 not much else we can do. 1200 miles.
It's normal as far as I can tell. Most of my FCA products have done it. Most car parts stores will check engine codes for free though if you want confirmation of any stored codes.
I am also looking into the flex kit. Did you opt for the kit with new shocks? I'm a little new to all of this and right now me and the wife are debating on the mopar kit or the RK flex.