To those of you that are mentioning 'best qualified', pool 2, pool 1, etc. I received a TOL at the end of February as a pool 2 North East applicant. When I had called HR at the start of February, they had told me that more selections could be made but most likely they were under the impression that no further selections would be made and I would have to reapply. Just because you weren't accepted yet, does not mean the ATO will not get around to selecting you.
The reason why some people that are in the 'best qualified' category but were not yet selected could also be due to the personality test that was given during the exam. It isn't clear if the personality test factors into your score of being 'best qualified' but if you had failed the personality quiz, that could be a reason why you were not selected.