What I talked about is the practice that oftentimes when the government introduces proposed tax measures, it will start implementing them right away, and they are always subject to parliamentary approval. A government might announce that it will start to put it in place and implement something down the road, and then a bill is adopted with a date going back to the date of the announcement. That certainly can happen.
In this case the bill was adopted with no date, and therefore it comes into force on the date of royal assent as per the Interpretation Act.