This confused me for a while so I thought I'd raise it here for your consideration.

Two issues

• 'what numbers are used in calculations'; i.e. do calculations use reals or percentages?
• should calculations take account of settings controlling the use of 'all'/'non-empty' grades?

Example:
I have 3 quizzes in one category.
My scores in the Gradebook are shown as percentages.
I show the average for the category - the 'calculation' field is empty.
The average is shown as a percentage.

Now
I complete the 'calculation' field with '=average([[quiz1]],[[quiz2]],[[quiz3]])'
And the resulting average is shown as a real.
And the calculation uses all entries - even though my aggregation for this course is to use non-empty grades.

So I have two ways of calculating the average for these three quizzes which give very different outcomes and that is somewhat confusing.