The department shall by regulation establish a classification of goods and services for convenience of administration of AS 45.50.010 - 45.50.205. However, the classification does not limit or extend the applicant's or registrant's rights, and a single application for registration of a mark may include all goods upon which, or services with which, the mark is actually being used comprised in a single class, but in no event may a single application include goods or services upon which the mark is being used that fall within different classes of goods or services. To the extent practical, the classification of goods and services should conform to the classification adopted by the United States Patent and Trademark Office.