Parking lots in the C-1B Commercial District may only be used for those off-site commercial and industrial uses that are situated on a parcel, tract or area of land, used or developed as a collective or unit, that is located within 1,000 feet of the boundary of the C-1B Commercial District, provided, however, that the Planning Board may waive this distance requirement if the Planning Board determines that such use will not cause a deleterious impact on the surrounding area.