"Mixed Use Planned Unit Development" or MPUD shall mean an area of land in which a variety of office , light industry, warehousing, retail and wholesale building types and densities are accommodated in a pre-planned environment under more flexible standards, such as lot sizes and set-backs, than those restrictions that would normally apply under these regulations. The procedure for approval of such development contains requirements in addition to those of the standard subdivision, such as building design principles and landscaping plans.