A construction cost estimate sealed by a registered architect or professional engineer using industry standard estimating guides or software, compared with recent cost experience in the local market. The method for calculating shall be based upon a cost per square foot derived from project classification (occupancy), construction type, building height, total square feet of occupied space, and a location multiplier, and shall include all requisite architecture and engineering necessary for occupancy. A separate cost per square foot shall be calculated for unoccupied space, including but not limited to basements, parking decks, and mechanical spaces. Specialty items, such as custom millwork, carved stone, and decorative metals, shall be calculated as a lump sum separate line item. The three values shall then be added to establish a total construction cost.