A unit number is assigned by a developer, a managing agent or a local authority, and what it records is usually the geometry of the building rather than anything about the dwelling. In most schemes the leading digit is the floor and the rest is the position along the corridor, so unit 703 is the third door on the seventh floor. Reduced, that gives ten and then one, and the reading attached to one is then offered as a description of the household.
Two consequences follow that a reader should hold in view. Identical dwellings stacked vertically get systematically different readings, because only the floor digit changes between them, and neighbouring dwellings on the same floor get readings that vary in an orderly sequence along the corridor. Whatever the numbers are describing, it varies with position in a building in a way the building's designers chose.
There is also the omission that runs through every scheme of this kind. Many buildings have no thirteenth floor, and in parts of East Asia no fourth, because the developer removed the number for exactly the sort of reason numerology is interested in. The unit numbers above the gap are therefore all shifted, and a dwelling physically on the thirteenth floor carries the number fourteen. A superstition about numbers has quietly altered the input to a system that reads numbers, and neither the practitioner nor the client is likely to notice.