A. For low income senior citizens’ apartment projects with from sixteen to twenty dwelling units, the minimum setbacks and special yards shall be as required in the underlying zone.

B. For low income senior citizens’ apartment projects with more than twenty dwelling units, the minimum front, side, rear and special yard requirements of the underlying district and the locational requirements for accessory buildings in the general zoning regulations shall be superseded by a requirement of a minimum ten-foot setback around the periphery of the project site; provided, however, that nothing contained in this section shall limit the authority of the planning commission or the city council on appeal to require a greater setback. Encroachments of up to five feet into said ten-foot perimeter may be approved by the planning commission or the city council on appeal, as follows: