‘Lowest offered Atar’ Query

My main question is how does this work?

Currently in yr 12, with a predicted atar of around 77. Attempting to get into engineering, specifically mining at curtin. I know that in unit 4/ sem2, the courses you do get a bit easier, and (so far) my marks have been going up, so that now I’m getting roughly 79-81.

The main concern of mine is the scaling. From what I can tell, my school scales extremely bad (one of the worst in the state of WA). So I’m afraid scaling will ruin my atar and thus chances of getting into engineering which requires that sweet 80

Now I’ve noticed that on TISC there’s a ‘lowest offered Atar’ listed. This is great because, specifically for my course, the lowest is 72 (in comparison to guaranteed 80). Back to the main point, how does this work?

For further background info, the school is go to is low socioeconomic (eligible for Step up program which grants up to 5 Atar points). I’m of a second gen migrant background from oppressed nation (not indigenous). I also do ‘SIDE’ (long distance education for Methods in which is used when the class is smaller than 5 people) which I know is accounted for, and then I do the big 4 ATARS, Eng chem physics and methods.

Any assistance would be great, knowing that I don’t have to worry about barely missing out due to something I can’t control