This is wrong. According to your scenario, you've got first place raw = 80, first place exam = 98, and first place moderated assessment mark = 84. No. If first ranked gets 98 in their exam, and that is the highest exam mark, that student will definitely get 98 for their moderated assessment mark, their exam mark, and thus their final HSC mark will be 98, not the average of 98 and 84.
Your assessment marks are also wrong, even if I don't mathematically calculate it to the decimal. The first ranked person will get 98 for their assessment mark, and the last ranked person will get 76 for their assessment mark. First and last are pinned - they give the range of marks distribution. Then, BOS calculates the mean of the exam marks, and the mean of the raw marks, and aligns them together. Then, by a process of standard deviation from the mean, moderated assessment marks are generated.