Hello.  A remark. You are an experienced mapper and managed to map a high building incorrect (Both the roof and sidewalls)
Please check this out.
About complex buildings. Especial the high rise (multi story) buildings and buildings which shows their side views as well. Check this footage how to map these buildings 
https://www.youtube.com/watch?v=dsfUcslLtVc
https://drive.google.com/file/d/13RTwH7sChRWrG5bIjysF2ripBgh3F5l4/view?usp=sharing 

Lower buildings, showing their sidewalls as well, can be mapped on the same way by moving the mapped roofline to the groundplan.

Best regards and keep mapping

