Here in our part of Oz, the education system uses the most recent score for any subject to calculate a students tertiary entrance rank which I think is very reasonable. This is the third year of our sons HSC campaign and he has another year of school to go. Any score of 98+ is ceiling bumping, so he decided at the outset that he would only retake a subject if he scored less than 98 (he has scored 98 in two of two exams so far). His principal recounted an anecdote of a pupil at his old school who scored a 96 in music (which is pretty exceptional given that assessments are more subjective in this field) and agonised over whether to retake the subject.

During my time in high school, they took an average of all attempts to calculate the tertiary entrance rank. I prefer the current system. I took no chances, however, and requested written confirmation from the principal that only the most recent mark in each subject was applicable.