(a) If all or part of the district territory is annexed by a municipality that has adopted and is imposing a sales and use tax, the sales and use tax imposed by the district in the annexed territory shall be reduced, if required, in even multiples of one-eighth percent, and without the necessity of an election, so that the combined rate of all sales and use taxes imposed by Henderson County, the annexing municipality, and all other political subdivisions within the annexed territory of the district will not exceed two percent, except that:
(1) a sales and use tax previously adopted by the district for the annexed territory may not be reduced to less than one-half percent; and
(2) a reduction of the district’s sales and use tax in the portions of the district that are not annexed is not required.
(b) Not later than the 10th day after the date of the annexation or exclusion of territory by the district or the annexation of all or part of the territory of the district by a municipality requiring a reduction of the district’s sales and use tax as provided by this section, the board shall send to the comptroller, by certified or registered mail, certified copies of all resolutions, orders, or ordinances pertaining to the annexation or exclusion of the territory by a district or municipality.