Yes, that's true. A Homogeneous part has the same graphics and pins in all sections, that means the you will have multiple power pins and they, in turn, must be consistently connected to get the part packaged properly. A Heterogeneous part can have different graphics and pins in each section, such as having the power pins in one section, and not in others, or having the power pins in a section on their own.
Back annotation, or not, doesn't really come into it. You can have Homogeneous, or Heterogeneous, parts as required for design convenience. Homogeneous parts are a little more simple since the graphics are only created once for all the sections but the power pins need to be take care of between the sections in the schematic. Heterogeneous parts allow more flexibility with graphics and pins but need a bit more effort to create, Equally, some parts. like large processors and FPGAs, "pretty much" have to be designed as Heterogeneous parts.