yes sounds about right, i am 20 mins stop start and get only about 25mpg, about 280-300 miles to the tank...on longer trips I have managed 360 miles to a tank.
I am monitoring my usage via the Road Trip app on the iphone, seen 29mpg and 24.5 mpg recently, I sometimes think i would be better taking a longer more cruisey route into work to improve my mpg!