Isn't there any dropdown menu to select properties? Does it register AVE? or Avenue? Also, you're asking the user to make a lot of guesses and estimates, kind of takes away from the precision of a "calculator"
I'll be moving to a MBP when the next refresh hits from Ubuntu as well, and I plan on running Windows in a VM if I ever need to. I'm sick of having to deal with Linux's shitty support for iDevices, as well as the awful battery life.