I'm not sure what is happening. Where in the forum are you posting? They should be counting.
If I'm understanding this right, the post counts will be the same. Every time you post something, the count goes up, and it goes up on all previous posts. So if you look back at a previous post, (even a really old post) the post count will be the same as the most recent post count. Am I making any sense?
(It's just like when you change your avatar or siggy - it will change on all previous posts)