A. Whenever any employing unit succeeds to substantially all of the employing enterprises of another employing unit, then in determining contribution rates for any calendar year, the experience rating record of the predecessor prior to the succession shall be transferred to the successor and thereafter it shall not be treated as the experience rating record of the predecessor, except as provided in subsection B. For the purposes of this Section, such experience rating record shall consist of all years during which liability for the payment of contributions was incurred by the predecessor prior to the succession, all benefit wages based upon wages paid by the predecessor prior to the succession, all benefit charges based on separations from, or reductions in work initiated by, the predecessor prior to the succession, and all wages for insured work paid by the predecessor prior to the succession. This amendatory Act of the 93rd General Assembly is intended to be a continuation of prior law.
     B. The provisions of this subsection shall be applicable only to the determination of contribution rates for the calendar year 1956 and for each calendar year thereafter. Whenever any employing unit has succeeded to substantially all of the employing enterprises of another employing unit, but the predecessor employing unit has retained a distinct severable portion of its employing enterprises or whenever any employing unit has succeeded to a distinct severable portion which is less than substantially all of the employing enterprises of another employing unit, the successor employing unit shall acquire the experience rating record attributable to the portion to which it has succeeded, and the predecessor employing unit shall retain the experience rating record attributable to the portion which it has retained, if–
         1. It files a written application for such experience