After looking into your spreadsheet , I have noticed that you have counted posts from August 11 to 16 (in the starting posts and ending posts) while you have paid only for August 11 to 15. while counting you should have to keep in mind that you have to leave the Monday posts for the next week, but you did not leaved them and counted in the ending posts.

for example if a person has completed 295 posts till monday and the 5 posts are from monday, then the ending posts of that person are not 295 but they are 290.