The first problem is that the UAI is a rank, comparing all students in a cohort to one another. Because accelerants complete their HSC over two or more years, their final UAI is calculated with scores achieved in a different cohort. While some allowance for this is made in the calculation both of the UAI generally (one of the improvements over the TER it replaced) and for accelerants in particular, scores for subjects in the student's final year generally carry more weight. Since an accelerant is unlikely to be accelerated in the first place unless the subject is their major strength, this carries less weight than it should.