An additional charge of the business license tax being assessed to and paid by all businesses within the boundaries of the parking and business improvement area is hereby imposed, commencing August 15, 1984, in accordance with the benefit zones as provided in Section 21B-7.4, and in accordance with the classification of businesses in Section 21B-7.5. Payments of a similar charge by any businesses which are now exempt under the Constitution of California from payment of a business license tax shall be on a voluntary basis. (Ord. No. 1902 (NCS), § 1.)