Frankly, Poser tends to be pretty dumb when searching for files. For starters, the path doesn't have to be wrong for it to get lost - it simply fails to look at all the runtimes as it claims in the manual. A perfect example of that is when you tell it where a texture is, and it keeps asking for the path for all subsequent textures, even if they are all in the SAME path you have just provided. In other cases, all the paths are correct, but Poser sometimes assumes that all items on the scene must come from the same runtime - usually the last one used. When I create new contents, they are in a different drive, and Poser gets confused even when all paths are properly registered as external runtimes. Whenever I access an item from a runtime that is located at a different drive, Poser gets lost if the next item is not in the same drive. It keeps looking at the last place, instead of searching the registered external runtime paths.
So it doesn't matter if we set Shallow or Deep, it's a waste of time either way. It's just that Deep is a bigger waste of time than Shallow. LOL