I asked a co-worker, and we seem to think that file placement within a directory is based on the OS's strange preferences; we don't know the rhyme or reason for it. For example, try this on UNIX:

ls -lf
[download]

This lists a directory contents without sorting. Note the apparent arbitrariness of the file order... so, even if there are identical files in two directories, there's no guarantee that a directory listing will return them in the same order.

That's the best we can offer for an explanation.

rje