Keep in mind that the Assessment Marks are adjusted to equal or be similar to equivalent Examination Marks. Examination Marks are the primary element here, not the relative gaps. If an entire cohort receives unfavourable Assessment Marks, then that is caused by unfavourable cohort performance in the HSC exams. Similarly, if some students receive unfavourable Assessment Marks, this will be because the equivalent Examination Marks themselves are unfavourable. Relative gaps may be changed slightly although they will remain close to the original (for example, an original gap of 12 can become 15, see the
graph from NESA). More importantly, they will not be significant enough to prevent a high performing student from receiving an Assessment Mark in the top range. With that being said, it is definitely possible that an Examination Mark of 90 leads to an Assessment Mark of 89 for example.