With respect to the application of penal provisions to an act committed before this Act (with respect to the provisions set forth in item (xv) of Article 1, paragraph (1) of the Supplementary Provisions, before those provisions) comes into effect, and to an act committed on or after the effective date of item (xv) in a case where those provisions are to remain in force under Article 36, paragraph (1) of the Supplementary Provisions, the provisions then in force continue to govern.