There is delegated to the planning commission the power to grant exceptions from the provisions of this title, upon its own motion, or upon the verified application of any property owner, as to the maximum overall height of any sign above natural ground level or as to the maximum square feet of advertising surface, whenever one or more of the conditions hereinafter set forth exist. In the exercise of the power herein delegated, the planning commission shall impose such conditions upon exceptions so granted as in its judgment may be necessary to assure that the spirit and purpose of this title will be observed, public health, safety and welfare secured, and substantial justice done. As to the existence of any of the hereinafter set forth conditions and the necessity for exception from the provisions of this title, the burden of proof shall be upon the applicant, and in all cases the applicant must establish that the location applied for is the most suitable and effective in relation to the natural terrain of the subject site from the standpoint of the intended viewer. (Ord. 89-3 (part), 1989)