Hi, my first response, having worked with hundreds of instructors using the gradebook, it not to use Sum of Grades unless the instructor fully understands the math behind it. Everything needs to synch with the course outline, so I always ask to see this first before I even start helping someone. I have found in many cases, that the instructors don't fully understand how weightings work, or how to properly aggregate grade items within a category. You might want to post their course outline to see how they are assessing the course materials as I believe the aggregation being used in this case is not correct?
D.