Multiplicator factor seems to be ignored when added to a grade item. To reproduce the bug:
1. in a course add a graded activity, such as a quiz. Configure the quiz so students can score a maximum of 10.
2. allow for some attempts from students.
3. enter the course gradebook.
4. select "categories and items"
5. edit the quiz item
6. in the Multiplicator box enter a value such as "33.333". Offset Grade display type: Real.
7. save changes
8. Show the grader report. The quiz score is not multiplied by the multiplicator