It will get better as it breaks in, make sure the tire pressure is at the rated max and the air cleaner filter is spotless. A couple of mpg is nothing to make a stink about, it can easily be attributed to driving habits and other variables.
Since when did you ever trust a mfg to give accurate/realistic mileage ratings anyway Turbo?
“She may not look like much, but she's got it where it counts, kid. I've made a lot of special modifications myself.”
— Han Solo