Your driving conditions and style have so much more to do with your mpg than anything on the car itself, barring serious mechanical problems. Tell us more about your commute, how you accelerate/brake, how fast you drive, does someone else drive it, etc.

Under 1K miles...so your on your 2nd tank or so...ignore the 1st tank if it had test drives, etc on it.

Look in the mileage database to see individual driver's tanks. You'll see a lot of lower-mileage HAHs in the 25-30 range, so no, you are not terribly off the norm.

Feather the gas pedal, and try to keep the eco light on as much as possible. That's the only way to get >30mpg tanks for most people and conditions.

Expect to see a nice increase (~1 or 2mpg) around 1500 miles as the engine breaks in, and again around 2500 or 3000.

There's a raging debate about gage accuracy. Navi gets its distance input from GPS, the dash gage from the wheels actually going roundy-roundy. Both get fuel consumption from the onboard engine computer. Different types of errors abound in all 3 inputs. Pick your poison.

You need to calculate your "real" mpg at the pump by hand for several tanks, and decide which gage you prefer to believe day-to-day. And neither will exactly match your hand calculation. IMHO, anything that is normally within 1mpg of what you calculate is close enough, given all the sources of error. Navi has the nice feature of displaying your instantaneous mpg, though, which is very helpful for adjusting your driving technique. The dash is just the average since the last reset.

Your driving technique will also improve as you read around here and adopt some new methods, should you choose to. That can yield the greatest gains.