The language of the act is neutral enough not to set a timeframe as to when the person has to notify. There are two steps. The first step is we have to pay you, we have to reinstate payment. When? When you let us know that you will be released or you are released, payment will occur.
The text says they must “notify the minister in writing of their release”. The text does not say to notify in writing that they have been released. Therefore, from our perspective, it is neutral enough, because it's just talking about an event. The event is a release.
So technically you can notify prior to your release.