Redetermination of tax increment base when project costs increased by amendment of plan. 11-9-23. If Except as provided in this section, if the municipality adopts an amendment to the original project plan for any district that includes additional project costs for which tax increments may be received by the municipality, the tax increment base for the district shall must be redetermined pursuant to § 11-9-20. The tax increment base as redetermined under this section is effective for the purposes of this chapter only if it exceeds the original tax increment base determined pursuant to § 11-9-20. The provisions of this section do not apply if the additional project costs are thirty-five thirty-11 five fifteen percent or less than the amount approved in the original project plan and the additional project costs will are to be incurred before the expiration of the period specified in § 11-9-13. 14