The Individual Address is structured in the following way: Backbone coupler. Line coupler. Bus coupling unit.

True. In a multi-area, multi-line KNX TP topology, an Individual Address a.b.c expresses exactly that hierarchy: 'a' identifies the area (and therefore the backbone coupler that fronts it), 'b' identifies the line within that area (the line coupler), and 'c' identifies the individual device (its bus coupling unit) within that line. The same three-level structure is what couplers use to filter and route telegrams.

Reserve 'x.x.0' for couplers and 'x.x.255' for line power supplies in your numbering plan — readers of the project will then identify the function of a device from its address at a glance.