The provisions of Part IV, Chapter II, Section 1 of the new Income Tax Act and Appended Tables II through IV of the new Income Tax Act apply to salaries or other wages prescribed in Article 183, paragraph (1) of the new Income Tax Act which are payable on or after January 1, 2005, and the provisions then in force continue to govern salaries or other wages prescribed in Article 183, paragraph (1) of the former Income Tax Act which were payable before that date.