The provisions of Article 225, paragraph (1), items (iii) and (viii) of the new Income Tax Act apply to compensation for periodic deposits, finance charges, profits, or margin profits prescribed in item (iii) of that paragraph (hereinafter referred to as "compensation for periodic deposits or similar amounts" in this paragraph and the following paragraph) and to domestic source income prescribed in paragraph (1), item (viii) of that Article (limited to that set forth in Article 161, item (xi) of the new Income Tax Act; hereinafter referred to as "domestic source income" in this paragraph and the following paragraph), which are to be paid on or after April 1, 1988, and the provisions then in force continue to govern compensation for periodic deposits or similar amounts and domestic source income which are to be paid before that date.