Per activity weights

Each activity should be capable of having individual weights. Here is a use case example.

A math teacher has multiple tests. Tests are weighted as 60% of the final grade, something schooltool already does well.

Each test however should have different weights. This should be some type of preference to enable weights per activity.
Test 1 points: 10 weight: 100
Test 2 points: 20 weight: 50
Note that once weights are enabled, we must enter a weight on each activity

If student a gets 5 points on test 1 and 10 points on test 2, their grade should be
5*(100/(100+50)) + 10*(50/(100+50)) = 6.67 points out of a total possible 13.33 points.
Thus the student's test score would be 50%
Afterwards weights on the test category would be applied to calculate final grade.

This functionality does exist in GradeQuick, which has a preference setting to either operate as described above or as SchoolTool currently operates.