Penalties and interest.
(2) Penalties and interest. The IRS may impose a penalty, addition to tax, and additional amount with respect to any imputed underpayment determined under this section in accordance with section 6233(a)(3) (penalties determined from the reviewed year). In addition, the IRS may impose a penalty, addition to tax, and additional amount with respect to a failure to pay any imputed underpayment on the date an AAR is filed in accordance with section 6233(b)(3) (penalties with respect to the adjustment year return). Interest on an imputed underpayment is determined under chapter 67 of the Internal Revenue Code for the period beginning on the date after the due date of the partnership return for the reviewed year (as defined in 301.6241-1(a)(8)) (determined without regard to extension) and ending on the date the AAR is filed. See 301.6233(a)-1(b). In the case of any failure to pay an imputed underpayment on the date the AAR is filed, interest is determined in accordance with section 6233(b)(2) and 301.6233(b)-1(c).