I'm a little confused about what the question is, but I think there is confusion about how bumping works.
Bumping will move your post to the first page, as if a post was made, but a post isn't made, and the last activity still shows as the last post. However, naturally it will drop again as other members bump and post, and sometimes things do move fast.
So no, you don't and shouldn't post as well as use the bump feature, everything seems to be working fine but if I'm misunderstanding the question, let me know.