Household address leaves data in Contact Address if that Field in Household address has no data

COntact A and B at same address - but the address fields are out slightly, eg one has Suburb in Supp 1 and other has Suburb in Supp 2.

When I use Contact A to create New Household address and then apply that address to Contact B, the Suburb appears in both Supp 1 and Supp 2.

What I take from this is that applying the Household only writes the Household address in to fields that it has info for, and leaves the others as they were.

I think instead it should take over 'blank' fields too, to ensure that old 'address' details are not retained. Does this make it clear what the problem is?