Hello. Thanks for mapping.
Your mappings here are very basic. Just a (large) rectangular around a complex building. Please follow the rooflines and where trees cover it, just extrapolate the roofline.
Another building is mapped way to big. 
Check this webpage. 
https://overpass-api.de/achavi/?changeset=164510334
My adjustments are in green.
Best regards and improve you mappings.