Unless you get a Supervisor from the ATO I have received too much conflicting information from them to count on their expertise. Usually what they tell you is documented though - so each time you ring them, make sure you identify yourself (TFN) and ask for the conversation to be documented. Recently I had a five month ongoing issue for my Business account - because it was all documented and ATO people could see I was given the wrong advice, at each stage they were helpful (even when they were wrong!) and it wasnt until I was put onto a senior auditor who could see the trail of mistakes they had made, and put everything right for me, and waived all the (incorrect) fines they had imposed. I never lost my cool with them, it actually became quite laughable at the series of mistakes the help desk had made, and the senior person was very apologetic for all the angst I had been put through. So I am hoping I now have a few brownie points with the ATO!
And this service was provided by the Help desk for Business BAS - you would have thought they would know what they are doing, wouldnt you!