I do not know what programming magic is going on there, but I can confirm that something is indeed wrong for the SUM in some scenarios.
I believe SWM and WM are ok.
SUM does not like having hidden items anymore if you:
a) set User report to Show Totals Excluding Hidden Items (previous functionality was to include them always)
b) Maximum Grades for your gradable items are different. If they are the same, you should be fine, as far as I can tell.
I understand that the gradebook tries to do some silent conversion of the total because of that, but I cannot figure out any logic in calculation to point to the exact error.
Scenario: Add two items with differentmaximum grade to a category with SUM
A1 - out of 100 points, A2 out of 50 points. Hide A2. Our category total is 150 points.
Give 100 points to a student for A1.
User report will show 75.00 (50.00 %)
Grader report will be OK, showing 100.00 (66.67 %)
To "fix" temporarily:
- Switch to SWM, or
- Set User Report to "Include Hidden items" into the total. Kinda defeats the purpose, but if you do not show percentages to your students, they would not care at all.