Quirrell could have decided that their overall grades should reflect only their ability to defend themselves, and so chosen to adjust the non-exam grades such that each student’s overall grade (with the final included) matches his assessment of that student’s defensive ability.
(This is really a more detailed version of your second guess.)
Quirrell could have decided that their overall grades should reflect only their ability to defend themselves, and so chosen to adjust the non-exam grades such that each student’s overall grade (with the final included) matches his assessment of that student’s defensive ability.
(This is really a more detailed version of your second guess.)
It could mean that, by surviving this long, Harry has exceeded Quirrell’s expectations.