(1) To adopt a new urban renewal plan or create a competitively disadvantaged border community area containing a revenue allocation financing provision, the local governing body of an authorized municipality must enact an ordinance in accordance with chapter 9, title 50, Idaho Code, and section 50-2008, Idaho Code. To modify an existing urban renewal plan, to add or change a revenue allocation, an authorized municipality must enact an ordinance in accordance with chapter 9, title 50, Idaho Code, and conduct a public hearing as provided in section 50-2008(c), Idaho Code. No urban renewal project, plan, competitively disadvantaged border community area or modification thereto, or revenue allocation financial provision shall be held ineffective for failure to comply with the requirements of this section if compliance with the section is substantial and in good faith and administrative authority of both the local governing body and urban renewal agency does not extend beyond the municipal boundary of the authorized municipality. Urban renewal plans and revenue allocation financing provisions may be held ineffective if an urban renewal area or revenue allocation area extends outside the municipal boundary of an authorized municipality and a transfer of powers ordinance has not been adopted by the cooperating county.
(2) A revenue allocation financing provision adopted in accordance with this chapter shall be effective retroactively to January 1 of the year in which the local governing body of the authorized municipality enacts such ordinance.