@trostlechet did the letter specify the exact reason for the additional tax?
if the State have record of an income item that you did not post on your federal or state tax return, that could be the reason. Hard to tell without additional detail.
Turbo Tax guarentees their software produces the right result; however, what they do no guarentee is that you entered the form without error. If the form is not entered correctly, the output will also be incorrect - TT says "not my problem!".
