When preceding comments get deleted from an original post,doesnt it immediately change the number of posts the topic has already, how are we going to keep track with the number of deleted posts and the original ones

Also there is never a time posts come to a culminating end, comments keeps coming in even after many months or so, there are threads on this front page that are over 6--7 months old
How then can you end calculations when comments are still coming in that very thread/topic