I’ve added a column to the "Merit per Post" tab called nMeritedPosts, that counts the distinct number of posts merited within the given board and month.

Notice that the toll is counting the number of posts that have been merited withing the meriting timeframe, not withing the posting timeframe. That is to say, I’m counting based on when the meriting event takes place, not when the posting event takes place.

Note: I'm updating the Dashboard now. Give it 5 minutes or so to complete.