If you're Supporter, VIP, Veteran, Moderator or Admin, the amount of posts you got wont effect the rank that is shown, cause does are special ranks and will go over top of what you got from your post amount.
As an example, I am Redstone Miner cause I done over 1000 posts in total, but as I am VIP, it shows my rank as VIP and not Redstone Miner.