I was incorrect in my comment - Lacerte does subtract the underpayment interest from the refund.  However, Lacerte also incorrectly subtracts the underpayment interest from the difference between the Wisconsin tax liability and the Wisconsin tax payments (Line 40 of WI Form 1). The underpayment interest should only be subtracted from WI Form 1 Line 41 not from both WI Form 1 Line 40 and Line 41.