Yes I'm pretty sure it is true that if you put pen to paper you get 50. It's made to be that way. but its not really something you want to be relying on if you are serious about your studies (which you are to some extent, from my impressions anyway)
Yeah I think I averaged around high 60s-very low 70s raw, but after scaling I was always comfortably in the 80's, well actually thats low 80s.
If it helps, a friend of mine usually either failed or just passed internally but after scaling got herself a high 60s. didnt really improve much for the exam but i think ended up with a high 60 overall still. That's not too shabby.
Two unit scaling is good, but I love three unit scaling. I think I only ever got 57% tops in an exam, failed both the trial and first assessment task and still got 70 after scaling internally (because we had marks scaled after each exam). I get to the HSC exam, attempted just over half of questions (as in left rest blank), and I dont think there was any way I could have passed in the end. Come HSC results day, 74%! Ahhhh I love scaling and how it masks mediocrity