Buildings of at least two (2) stories containing both residential and commercial uses, as described in subsection 11-4-2B14 of this title are permitted in certain commercial districts where, if new construction, the minimum area of the lot shall be not less than six thousand (6,000) square feet, and a ratio of total floor area to lot area shall not exceed eight-tenths (0.8), except in the CBD district where the only requirement is the provision of off street parking. In all cases the required off street parking shall be the sum of that required for the residential use and the commercial use, unless the periods of usage will not be simultaneous as determined by the planning commission. (Ord. 5916, 8-9-1999)