I'm so sorry for so many rejections today. I've been having a bad day, and the weather, and now so many bad news from the forum really depress the hell out of me. It seems to me that they did not consider the fact that Sydney has granted the 5 adaptability points last year, and what's even harder to accept is that it seems they refuse to consider additional work experience letter.
aidina, I'm wondering if you will consider appealing, or at least, send an email that explains why your letter describes the job duties and lead statement of NOC 4012 substantially. Also include the part from OP6B that states that an officer must consider work experience, for which an applicant has submitted documentation (since they seem to have considered it anyway, then you should focus your attention on highlighting why you think your letter matches NOC descriptions).
Obviously the chance is slim, but while waiting to hear back from them, then you do your new application.
The thing is, it's hard to gauge how many hours exactly we can claim as TA/RA. For my letter of reference, I put down 20 to 25 hours a week, and no more, but a lot of successful applicants have put down 37.5 hours per week, so it's hard to say.
Also, for a study to be considered 'full-time', then it needs to at least 15 hours a week, so to hadikhan64, you should say that you're studying PhD full-time, and spend the rest of your working hours working for research. This was how I got 20 to 25 hours a week (it should be, really, 22.5 hours per week).