With the exception of exemptions and waivers granted, as set forth in this Division, this Division shall apply to all new single-family attached, single-family detached, two-family, two-over-two's, three-family, and multifamily residential dwelling units constructed in Prince George's County on and after January 1, 2026. Dwelling units for which a building permit has been issued, or for which a site plan application has been approved pursuant to Subtitle 27 of the Prince George's County Code prior to January 1, 2026, as set forth in Section 4-357(a) above, shall be exempt from the provisions of this Division. This would include phased development plans for which the Department of Permitting, Inspections and Enforcement has approved Plans On File (building permit plans submitted by the developer and approved by the Department) for various types of homes in the development prior to January 1, 2026. For, any site plan approved before January 1, 2026, the Plans On File subject to the site plan do not have to be updated to comply with this Section. Application of the provisions of this Division shall not require existing dwelling units to be retrofitted. Undergraduate and graduate student housing for public and private colleges and universities and private dormitories as defined in Subtitle 27 of the Prince George's County Code shall be exempt from this Division. The provisions of this Division shall not apply to a single-family detached dwelling that is built or subcontracted by an individual owner that is used as the owner's personal residence. Dwelling, townhouse as defined under Section 27-2500 of the Prince George's County Code shall be subject to Section 4-364 of this Division and shall otherwise be exempt from the provisions of this Division. Two-over-two's "Dwelling, two-family" as defined under Section 4-356(d) of this Division, shall be subject to Section 4-364 of this Division and shall otherwise be exempt from the provisions of this Division.