Developers were granted permission in May to change the use of Transport House - a four-storey office building in Victoria Street - into 30 residential properties.
Another planning application has been submitted to Sandwell Council to turn "airspace" at the top of the building into a new floor, creating the seven additional properties.
It could see the building end up with 37 new homes spread out over five storeys. The change of use from office space to residential usage is "due to to be implemented shortly", a planning report said.
The report said: "This proposal is to optimise the airspace above the building to provide one full additional storey.
"The proposed units will comprise five two-bedroom and two one-bedroom flats. Each unit will include an open plan lounge and kitchen and bathroom."
The application has been made by NewRose Properties Ltd.
Transport House went on the market for £1 million in September 2019.