How do I reduce the amount on the "State and Municipal Interest" line of my Wisconsin tax form by the portion of the interest deductible in Wisconsin?

I initially forgot to indicate the amount of the interest that was deductible for Wisconsin.  I amended my returns in TurboTax to reflect that a portion of the interest was from Wisconsin.  When I completed amending my return in TurboTax and saved the results, there was no change to the "State and Municipal Interest" line.  It was not reduced as expected by the amount of Wisconsin interest.