Here's a suggestion.
Drop the post count entirely. Don't bother displaying it on the thread at all. (I know this is possible as this is indeed done on another vBulletin forum)
People are funny; give them some kind of numbers and it becomes gold to them. Take it away then it's just that. Numbers.
You know, I actually like that. This always means we'll have to know each other by name, not by post count, and this insulates new people from targeting old codgers for that blue special PM "HELP ME!"....