A. On or before March 20th of each year, the assembly shall review and enact, if necessary, an ordinance establishing differential taxation zones for that tax year in addition to that defined in HBC 3.70.060. The establishment of additional differential taxation zones may be accomplished by adopting a map or plat by reference with appropriate designations in lieu of descriptions. The applicable taxation zones shall be designated on each taxpayer’s assessment notice.

B. At the time of annual review and adoption, if necessary, of additional differential taxation zones as provided in subsection (A) of this section, the assembly shall also review the percentage of mill rate applicable to existing differential taxation zones and adopt any modification by ordinance defining such taxation zones or the applicable differential rate.