Off-street parking shall be located on the same lot as the principal building or use to which it is accessory, except that parking space for business uses may be located on a lot within 250 feet of the principal building it is intended to serve, but only if it is determined by the Planning Board upon site plan review that it is impractical to provide the required parking spaces on the same lot with the principal building and provided that such spaces located off the site shall be located on property in the same ownership as the use to which they are accessory and shall be subject to deed restrictions filed in the office of the Registrar of Deeds of the County of Bergen, binding the owners and his heirs and/or assigns to maintain the required number of spaces available throughout the life of such use, and such spaces shall conform to all requirements of the district in which they are located.