TII-143 try removing the de-increment by 1

git-svn-id: https://source.sakaiproject.org/contrib/turnitin/branches/TII-142@82799 fdecad78-55fc-0310-b1b2-d7d25cf747c9
TII-143 document the fix

git-svn-id: https://source.sakaiproject.org/contrib/turnitin/branches/TII-142@82800 fdecad78-55fc-0310-b1b2-d7d25cf747c9