The Department of Fair Trading states “Chairperson does not have a deciding vote under any circumstances”.
I think this is badly worded (which is not that unusual with Fair Trading). Your vote still counts towards a simple majority. I believe what this is referring to is an additional vote to break a deadlock, as exists in Victoria and elsewhere.
In fact Section 8(3) of Schedule 2 of the strata Act says this:
The chairperson does not have a casting vote in relation to any motion but may vote in his or her own right if otherwise entitled.