Issues with Calculating Building Characteristics, Footprint, Roof, and Facade Areas using Overpass API and OSM Data

While calculating the facade, I am facing issue that the building is overestimating the facade for building having holes in middle. Here i am considering all the coordinates in building radious, for hole i am considering as inner ring and for outer side as outer ring, then calculating the facade separately and adding to the total facade in each direction, for inner ring i am not considering the adjacency.
Any suggestions why i am not getting correct facade?
Thanks in advance.