If a use occupies at least 40 percent of the floor area of a building or portion of a building, as applicable, pursuant to Section 118-40 (ENTRANCE AND STREET WALL TRANSPARENCY REQUIREMENTS), that fronts on Union Square East, Union Square West or 17th Street between Broadway and Park Avenue South, then the principal entrance to that use shall be located on such street. However, if more than one use meets these criteria, the principal entrance to only one of them is required to be so located.