The zoning requirements applicable to preliminary approval first granted and all other rights conferred upon the developer pursuant to subsection 17-19.1 whether conditionally or otherwise, shall not be changed for a period of two (2) years after the date of final approval; provided that in the case of major subdivision the rights conferred by this subsection shall expire if the plat has not been duly recorded within the time period provided in subsection 17-9.9 of this chapter. If the developer has followed the standards prescribed for final approval, and in the case of a subdivision has duly recorded the plat as required in subsection 17-14.3 of this chapter, the Planning Board may extend such period of protection for extensions of one (1) year but not to exceed three (3) extensions. Notwithstanding any other provisions of this chapter, the granting of final approval terminates the time period of preliminary approval pursuant to subsection 17-19.1, above for the section granted final approval.

In the case of a subdivision or site plan of fifty (50) acres or more, the Planning Board may grant the rights referred to in paragraph a of this subsection for such period of time, longer than two (2) years, as shall be determined by the Planning Board to be reasonable taking into consideration: (1) the number of dwelling units and nonresidential floor area permissible under final approval; (2) economic conditions; and (3) the comprehensiveness of the development. The developer may apply for thereafter, and the Planning Board may thereafter grant an extension of final approval for such additional period of time as shall be determined by the Planning Board to be reasonable taking into consideration: (1) the number of dwelling units and nonresidential floor area permissible under final approval; (2) the number of dwelling units and nonresidential floor area remaining to be developed; (3) economic conditions; and (4) the comprehensiveness of the development.