When a majority change in the ownership of a firm (business) is accompanied by a change in the business activity of the firm (business) and this change is sufficient to result in a reclassification of the basic classification assigned to the firm (business), then the past experience, prior to the change, shall be excluded from future experience ratings of the acquiring entity. If the change in business activities is not sufficient to result in a reclassification of the basic classification assigned to the firm (business), the acquiring entity shall retain the past experience attributable to the firm (business) or portion thereof which was purchased. For purposes of this rule, the term "basic classification" shall mean the classification other than standard exception classifications as defined in WAC 296-17-31018(2) which produces the largest number of worker hours during the calendar year in which the change in business operations is noted. The basic classification of a business shall be determined in accordance with WAC 296-17-31012.