Maximum Height: One hundred sixty ft., provided that the sum total of all building floor areas between one hundred forty feet and one hundred sixty feet shall not exceed twenty percent of the site area of the WTODOD. For purposes of calculating the height of a building in the WTODOD, height shall be defined as the vertical dimension of a building measured from the mean level of the finished grade at the building, or from the plaza level at the building, whichever is higher, to the mean height of the roof structure. Also, height shall not include: parapets less than five feet high, chimneys, flag poles, ventilators, water tanks, antennas, and other projections used for, or intended to be used exclusively for, utility services or access to the roof may exceed the height limitations of this chapter by not more than twenty feet.