(a) establish or increase lot areas or lot dimensions which are in excess of the areas or dimensions of the lots shown and delineated on a residential subdivision plat which has been duly approved by the planning board, or other board or officer vested with authority to approve subdivision plats, if any, of the town in which the land shown on said plat is situate and duly filed in the office of the recording officer of the county in which the land shown on said subdivision plat is situate; or

(b) establish or increase side, rear or front yard or set back requirements in excess of those applicable to lots under the provisions of the zoning ordinance or local law, if any, in force and effect at the time of the filing of the said duly approved residential subdivision plat or first section thereof shall not, for the period of time prescribed in subdivision two of this section, be applicable to or in any way affect any of the lots shown and delineated on such subdivision plat. 2. If at the time of the filing of the subdivision plat or first section thereof referred to in subdivision one of this section there was in the town:

(a) both a zoning ordinance or local law and a planning board vested with authority to approve subdivision plats, then the exemption provided for in subdivision one of this section shall apply for a period of three years after the filing of the approved subdivision plat or first section thereof; or

(b) a zoning ordinance or local law in effect in the town but there was no planning board in said town vested with authority to approve subdivision plats, then the exemption provided for in subdivision one of this section shall apply for a period of two years after the filing of the approved subdivision plat or first section thereof; or

(c) no zoning ordinance or local law in the town but there was a planning board vested with authority to approve subdivision plats, then the exemption provided for in subdivision one of this section shall apply for a period of two years after the filing of the approved subdivision plat or first section thereof; or

(d) no zoning ordinance or local law in the town and no planning board vested with authority to approve subdivision plats, then the exemption provided for in subdivision one of this section shall apply for a period of one year after the filing of the subdivision plat or first section thereof. 3. If such period of exemption would expire within one year from the date of the filing of a section of the approved plat, it shall be extended for that section for a period of one year from the date of the filing of such section.