Not quite. If the quota is 10,000 and one candidate gets 12,000 first preferences, what happens is that all of those 12,000 votes are looked at, and if 50% of them have a second preference for candidate X, then half of the surplus—that's 1,000 votes—would go to candidate X. It's not only the last 2,000 that are seen as a surplus; every single vote is looked at.
On July 26th, 2016. See this statement in context.