Section 7266 - Additions to tax(a) Failure to File Return. In the case of failure to file any return required by section 215 on the date prescribed therefor (determined with regard to any extension of time for filing), and in the case in which a return filed understates the true amount due by more than fifty per cent, there shall be added to the amount of tax actually due five per cent of the amount of such tax if the failure to file a proper return is for not more than one month, with an additional five per cent for each additional month, or fraction thereof, during which such failure continues, not exceeding twenty-five per cent in the aggregate. In every such case at least two dollars ($2) shall be added.(b) Addition for Understatement. There shall be added to every assessment under subsection (b) of section 231 an addition equal to five per cent of the amount of the understatement and no addition to the tax shall be paid under subsection (a) of section 231.(c) Interest. If the department assesses a tax according to subsection (a), (b) or (c) of section 231, there shall be added to the amount of the deficiency interest at the rate of three-fourths of one per cent per month for each month, or fraction thereof, from the date prescribed by subsection (a) or (c) of section 222 of this article for the payment of the tax to the date of notice of the assessment.1971, March 4, P.L. 6, No. 2, art. II, §266. Amended 1976 , April 14, P.L. 112, No. 49, § 1; 1997, May 7, P.L. 85, No. 7, § 4, effective 1/1/1998.