Note:

The taxpayer owes interest if the tax is not fully paid by the assessment date, even if the interest-free provisions otherwise apply.

If the taxpayer asks for an installment agreement beyond your installment agreement criteria or the agreed unpaid deficiency is over $100,000, coordinate contact between the taxpayer and a revenue officer through your manager. See IRM 4.20.1.4, Examination Collectibility, Installment Agreements, for more information.