Projects containing less than 160 units on less than 50 contiguous acres. The gross density for an inclusionary multifamily development on less than 50 contiguous acres may exceed six units per developable acre if more than 50% of the property, including wetlands, is to remain as permanent open space. In no event, however, shall the overall gross density exceed 160 dwelling units. Upon approval of the Planning Board, the developer set aside requirement for low- and moderate-income housing may be reduced from 20% to no less than 15% for projects that contain 160 units or less. In no event, however, shall the overall gross density, inclusive of developable and undevelopable lands, exceed 3.35 units per gross acre or have a low- and moderate-income housing set aside of less than 15%. The division between those units set aside shall be as follows:
[1] Low-income units: 50% of the total set-aside.
[2] Moderate-income units: 50% of the total set-aside.