1. Reductions in lot area in exchange for equal amounts of common open space on a one-to-one basis shall be provided in addition to the open space requirements referenced in paragraph A above.

2. For duplex lots where the duplex housing type is allowed only in a cluster subdivision, the lot reduction/additional open space calculation referenced in paragraph B.1 above shall be based upon the conventional lot size of a detached single-family lot for the zoning district.

3. For the townhouse or detached rowhouse housing type, the required open space shall be at least 20% of the gross area of the development.