If two (2) or more lots, combinations of lots or portions of lots with contiguous frontage are held in single ownership at the time of passage or amendment of this Chapter and if all or part of the lots do not meet the requirements established for lot width and area, the lands involved shall be considered to be an undivided parcel. In addition, the City of Pevely will treat subdivided lots as a single lot, provided that said lots are recorded as singly-owned. This exception will apply only to combinations of lots or portions of lots which occupy contiguous frontage and, furthermore, such subdivided lots shall be recorded and shall have constructed residences upon seventy percent (70%) or more of its platted lots. However, no new division of any parcel shall be made which creates a lot with a width or area below the requirements stated in this Chapter. Any variance of yard requirements shall be obtained only through action of the Board of Adjustment.