It really shouldn't matter to be honest.
In saying this however, it's my understanding that nearly all the First Year Chemistry units of study are scaled together as a whole. All the papers have a set of common components, which allows the school to make direct comparisons between different units and scale that way. Theoretically this would favour advanced units, since you would assume the advanced students would do better at the common sections. I should point out that all this was rumours going around between students, and should be taken with a grain of salt.
Additionally, I've linked previously to a University policy coming into effect which aims to eliminate the sort of scaling you're talking about; I think the name is "reference-based assessment" or something similar, basically where marks are determined by how you perform relative to the rest of the cohort. Instead, they want to move to standards-based assessment, where a set of standards is developed essentially describing what skills you would expect in a fail student, a pass student, a credit student etc etc. Assessments would then be written with these standards in mind so that a student satisfying credit standards gets a mark in the credit range, for example. This would mean that no scaling is needed and students get a mark which is highly reflective of, if not identical to, their raw mark for the unit.
A link to the policy:
http://sydney.edu.au/policies/showdoc.aspx?recnum=PDOC2012/267&RendNum=0
TL;DR: It's a little complicated and has very little affect on your final outcome. If you work hard and apply yourself, it will pay off.