I grade my classes with total points for the term. When I grade an assignment it gives the student a percentage grade along with the points. Students have trouble understanding that the percentage means nothing to their grade and they get nervous when they see a 63% on an assignment, but their cumulative grade is 83%.
The same thing goes with categories, by having a percentage grade for a category, it overwhelms students and parents alike. I do not weight my categories, so even if a student has a 72% in the quizzes category, they could still be earning an A in my class.
When a teacher grades in total points they should have the option or it should be the default to remove percentages for everything but the cumulative grade.