Multifamily dwellings at a density not to exceed 23.5 units per gross acre with 20% affordable set-aside for the entire site or amount agreed upon in court mediation or settlement agreements, subject to the provisions of § 348-8.18 and § 348-8.4, except none of the provisions shall be treated as variances but rather design waivers. Provision § 348-8.18M shall not apply when existing buildings do not include breaks. Provision § 8.18E shall not pertain so long as new buildings do not exceed the length of the existing building on-site, and no design waiver is required for existing conditions that are not exacerbated by new improvements.