I agree that it's a bit confusing that it doesn't do this, though it is intentional. It is mainly to preserve URLs that point to the file (e.g., so if you link to the file from a page on your site then the link won't break if you add a new version), and also becuase we consider that a new revision is really the same file, so keeping the same name makes some sense.

If you want a file with a different name on this second line then you have to add it as a new file (and optionally delete the old one).

Thanks

Joe - Voice Admin