Where the address should be is 'contentious' within OSM. Some think it should be where the post goes - a 'letter box'... 
However it should only be on one feature, that is the OSM guide. 

See https://wiki.openstreetmap.org/wiki/Addresses 

The role 'address' in a relation .. will probably be flagged as an error in the QA tools.. so those will need to be looked at. 