SECTION 5. IF WAIVER DOES

NOT APPLY

If neither the waiver provided by this notice nor any other exception applies to an individual taxpayer, the amount of any addition to tax is determined by applying the underpayment interest rate established under section 6621 of the Code to each required installment of estimated tax that was underpaid for the period that the installment is underpaid. The period of the underpayment runs from the due date for the installment to

the earlier of April 15, 2019, or the date on which the underpayment is paid. This notice has no effect on determining the amount of each required installment for an individual whose total withholding and estimated tax payments do not equal or exceed eighty percent of the tax shown on that individual’s return for the 2018 taxable year.