Two-family housing may not constitute more than 20% of the subdivision.
   (A)   In the event the development of a subdivision proceeds in phases, no phase may exceed the 20% two-family housing requirements.
   (B)   All lots or parcels designated as two-family residential lots shall be designated on the preliminary and final plats as required under this chapter. If such designation is not made, all lots shall be restricted to single-family residential use only.
('65 Code, § 1331.04)