The secretary shall, by legislative rule promulgated in accordance with the provisions of chapter twenty-nine-a of this code, establish a classification of goods and services for convenience of administration of this article, but not to limit or extend the applicant's or registrant's rights, and a single application for registration of a mark may include any or all goods upon which, or services with which, the mark is actually being used indicating the appropriate class or classes of goods or services. When a single application includes goods or services which fall within multiple classes, the secretary may require payment of a fee for each class. To the extent practical, the classification of goods and services should conform to the classification adopted by the United States Patent and Trademark Office. Until approved by the Legislature, the secretary may effect the purposes of this section by emergency rule.