Cannot associate Individuals with correct household when 2 or more households have the same last name.

Imported household data, then individual data via CSV.

I am trying to manually associate the individual with a household address (individual >> edit >> primary location >> select existing household) that already exists. For households with the same last name I select based upon the correct home address (in the auto complete selector) but upon submit the wrong household address will be stored. Remove address, retry - same issue.