interest and penalty on amended tax awed

[garfexwong]

Filed my tax early this month and expecting a refund.

however yesterday I just found out that a 1099-int was not included in my 1040. it is about $100.

I assume i can amend the return once i receive the refund.

my question is:

do I need to pay interest and penalty for the taxes owed of the 1099-int (20 bucks)? 

[Critter-3]

Probably not but if the IRS deems it necessary they will bill you for that ... when you amend the return mail in a payment with the tax form.