The NSW Act might be worded differently from in the ACT…
I just checked. NSW is very different. JT is right in NSW and I am right in the ACT.
In NSW: “In this Act, a resolution of an owners corporation is a “special resolution” if–it is passed at a properly convened general meeting, and, of the value of votes cast, not more than 25% are against the resolution…”
In my 51/25/24 example of yes/no/abstain, it would pass in the ACT and fail in NSW. The difference is that in the ACT the 25% against are out of everyone who could have voted at the meeting whereas in NSW it is out of only those who cast a vote, and abstaining is not casting a vote.
I prefer the ACT approach since the test is really about determining that there is not a substantial minority opposed and only those who actively vote ‘no’ are really opposed. People who abstain might be ambivalent, which is not opposition.