For any such development for which the Borough's land use ordinances (e.g., zoning or an adopted redevelopment plan) already permitted residential development as of the effective date of Ordinance No. 2017-10, adopted August 14, 2017, this requirement shall only apply if the Borough permits an increase in the gross residential density to at least twice the permitted density as calculated based upon the zone district's permitted front setback, side setback, rear setback, principal building height, floor area ratio, and impervious coverage (excluding § 2637).