Rooms. Any room other than a living room, dining room, kitchen, bathroom, laundry room, utility room, foyer or hallway shall be construed as a bedroom and every unit constructed shall be presumed to have at least one bedroom. The number of bedrooms per single family attached residential unit is unrestricted provided, however, the total number of more than two bedroom units shall not exceed the total number of two or less bedroom units and there shall not be more than 18 bedrooms per gross acre. Under no circumstances shall the bedroom mix result in a gross density that exceeds seven single family attached residential units per acre.