I recently recorded two videos on using Interactive Schedules to calculate the surface area of siding, gyp. bd., and flooring.
Check out the videos and accompanying blog posts:
Archicad Tutorial #93: Area Calculations for Siding and Flooring
http://www.shoegnome.com/2023/08/21/archicad-tutorial-93-area-calculations-for-siding-and-flooring/
Archicad Tutorial #94: Area Calculations for Wall Area by Zone
http://www.shoegnome.com/2023/08/27/archicad-tutorial-94-area-calculations-for-wall-area-by-zone/