(a) Each employer will have an experience-rated rate of contribution computed by the Board under the provisions of section 8(a)(1)(C) of the Railroad Unemployment Insurance Act. See subpart D of this part.

(b) Notwithstanding paragraph (a) of this section the rate of contribution applicable to an employer that first becomes subject to this part after December 31, 1989, will be computed by the Board in accordance with section 8(a)(1)(D) of the Railroad Unemployment Insurance Act. See subpart D of this part.