Hello,

Some parts of the building have a roof extension which does not match the real outline on the ground.  For those cases, I measured a difference of slightly more than 7.5 meters.
Indeed, we are lucky to be allowed to trace directly from government numerical data which has been licenced to use on OSM.

The picture below shows the difference between the official shape (pink) and how it was traced on aerial pictures (red outline).
https://multimob.be/uploads/urbis_err-8554636.png

Have a nice day.