Some of the post in the signature campaign will not be good especially if it is a month old.
As some of the post are deleted due to pruning.
DELETED thread is the main reason.. how can you come up the solution on this!
Pay for what we find. But everyone will get more.
As santino11 wrote, moderators sometimes delete whole threads and posts just disappear.
In situation when someone have longer conversation in mentioned thread,
his all posts can disappear. (It is extrem situation, but possible)
That's why in every signature campaign posts are counted weekly.