Hiya James
Scared to answer this TBH - found that the weighted mean grade my staff added caused no end of complications, exactly the same comment you have made was made several times.
Another issue was that staff would remove 'X' from the course but leave it in the grade calculation (unsure that you are using one), causing issues when the course was reset (crashed our Moodle instance at least twice). However, in your case, if you have test students, try adding grades to each component - see if the grade comes out right in the end? So saying, showing a 99% after one assessment is not cool - perhaps just show the actual grades?
Hope that that helps
Scared to answer this TBH - found that the weighted mean grade my staff added caused no end of complications, exactly the same comment you have made was made several times.
Another issue was that staff would remove 'X' from the course but leave it in the grade calculation (unsure that you are using one), causing issues when the course was reset (crashed our Moodle instance at least twice). However, in your case, if you have test students, try adding grades to each component - see if the grade comes out right in the end? So saying, showing a 99% after one assessment is not cool - perhaps just show the actual grades?
Hope that that helps