First make sure the hop IBU matches what you were sold. I know they can range. The AA% rating will be the default in the program.
Also I know beersmith uses some equation to determine IBUs but the IBUs come out on the higher side. I think there's a place to choose the method it uses to calculate as well somewhere in the app. Brew it, take note of the bitterness and then remember it. Watch each brew and learn what 55 IBUs according to the program tastes like.
Is your batch size set up correctly as well?