No, using ONLY the relative gaps. The ranks are only a symptom of the marks you and the rest of the cohort get, and other than 1st and last, the fact that you came say 10th is not used in calculating your moderated mark.
Definitely, the ranks are not explicitly used in any calculation. But the relative gaps rely on an ordering of some kind and the BoS do know which results belong to which student (according to my mum this wasn't the case with the SC a looong time ago). So put simply, ranks are a simple gauge and do matter even if just as a consequence of being calculated from the same data.
Hmmm so does first and last place's marks get pulled up or down by the cohort?
If they come first or last in the externals, yes. That is only for the external component of your mark though. With a lot of legitimate reasons for performing poorly in the external exams you can apply for special considerations which can exclude your result from the pool used to calculate the internal exam marks which in theory should stop a student ranked towards the bottom (for example) absolutely "carking" an exam and dragging down the student ranked last.
if you do good in the externals that guarantees a good HSC mark in the subject in the end, provided that your at the top of the cohort and the cohort performs relatively well
+1, I know plenty of people who have been dragged down by their cohort.
Old timer bosers know sanjay M, who ace his externals but got dragged down and had to go to uws for med. This was because of his cohort...
The 0.1% I was talking about is when a student due to questionable marking or easy assesments is tied first to a student who is unlikely to perform as well as them in the external exam.
In any other situation if a student claims to be significantly dragged down by their cohort, you have to wonder why they weren't ranked first. In the case of a contingent of slackers in a cohort this should be reflected in the relative gaps, if it is not then the problem is with assesments not differentiating students rather than the moderation process.
What you have to understand is any method has the potential to be an advantage and disadvantage for different students. A lot of the problems result from the fact that we only have the one external assesment to use as a benchmark. I think the system is relatively fair and despite the fact that aligning is to some extent a black box process I think the system as a whole is fairly transparent and predictable. If the BoS started using some magical algorithm in future I'd bet there would be even more misunderstanding and a lot more complaints from students.