10th Dirty Deed

a lot of people keep saying that theres a plot hole to the movie when they say that a new deed is added every time and that if there were 8 when "Mullet" did it and that someone else had to have finished the 9th deed which was find Duncan Rimes, which would have added the tenth, but have any of you ever thought to yourselves that maybe the 10th was added between when "Mullet" did it and when Zach did it? Like maybe that *beep* Lawton added it to get him expelled or someone added it because they knew that no one would get past nine because Duncan Rimes vanished? HUH?! DID YOU?!