IF it constitutes self-charged interest and your clients materially participated in the S-Corp, you'll need to compute the limitation for §1.1411-4(g)(5) offline.

This exception should be reported on Line 7 of F.8960 and the entry is found under Taxes > Other Taxes > Schedule J, Recapture, Other Taxes.  On the input screen, scroll down to the Net Investment Income Tax (Form 8960) section.  On the line for Other modifications to investment income [Adjust], enter the amount you computed offline.