In a multiple-family dwelling with dwelling units in excess of 200, there may be such service facilities as cocktail lounge, restaurant, barber or beauty shop, valet or shop for the retail sale of confections, tobacco, periodicals, stationery and similar incidentals, provided that:
[1] The service use shall be conducted primarily for occupants of such dwelling.
[2] There shall be no entrance to such service facility except from inside the building.
[3] No sign advertising such facility and no display of wares therein shall be visible from outside the building.
[4] The aggregate floor area of such service facilities shall not exceed 10% of the total floor area of the structure.