Sorry; moved it now.
My post count atm is 40, and my activity is 28. It used to go up at about the same rate, but then it just stopped at 28, which is why I'm wondering if there is a different limit. It also seems a bit too much of a coincidence that this happened right before Jr.
Make 2 more posts and let the magic happen. There is a formula somewhere in the section here. You should look for it as it is accompanied with much more information.
I'd copy it myself but then there'd be no work left for you.