Well it's all going to a central place in the flats, so without a specification on which flat how do we know which flat the letter belongs to - works well with

Well it's all going to a central place in the flats, so without a specification on which flat how do we know which flat the letter belongs to - works well with a house you own but the minimalism could mean your post being inadvertently taken. However it's a good show of how much ink/time is wasted normally on letters with useless data.