For single member electorates, the count is done by hand. On the night, they quickly allocate ballots to their first preference, and then they allocate them according to which of the two most likely winners is on top. (Usually, that means whoever came first and second last time, even if a repeat isn't all that likely, but with a powerful enough justification they sometimes make a different choice.) The full count is done by hand starting on Monday at the earliest. It may have to wait up to two weeks if it's close - government is formed on the basis of the unofficial, indicative counts.

OCR is mostly used for multmember electorates which aren't a problem in the US due to being prohibited by federal law (when they were used, it was block voting not proportional, so very badly antidemocratic). In that case, when the machines confidence is low, it gets done by hand.