CAD11 — CadBrep module issue

In the CadBrep module there are almost always two ways to traverse the topology: from the top level entities like Body to the underlying entites like Shell, Face, Edge, ... and the other way. For example I can get from Face to the OrientedFace which aggregates the Face or I can ask the OrientedShell in which Body it is contained. This does not make much sense to me. I always thought the topology is more or less hierarchical with Body is composed of OrientedShells which has reference to Shell and so on.
Unless I am missing something important, it is just some not so small overhead to have all those relations at hand and being uptodate with them. I would place such things in a client for I see it as application specific, if it is neccessary or not.