(a) Interest.

Interest, at the rate prescribed by the Commissioner of Taxation and Finance (see Part 2393 of this Title), accrues on any balance of New York State personal income tax, City of New York tax and City of Yonkers tax due from the due date of the New York State personal income tax return (determined without regard to any extension of time to file), to the date of payment.

(b) Additions to tax.

The additions to tax for late filing and late payment must be imposed on any balance of New York State personal income tax, City of New York tax and City of Yonkers tax remaining unpaid after the due date of the return, determined with regard to any extensions of time to file or extensions of time to pay, unless it can be shown that a basis for reasonable cause exists pursuant to section 2392.1 of this Title for such late filing or late payment or unless the provisions relating to the presumption of reasonable cause pursuant to section 2392.1 of this Title are met for such late payment.