I understand, before the 20% discount is applied, legislation needs to be passed first, so let's assume it won't be passed until later in the year (let's say July/Aug).
In this case, if I (using hypothetical numbers)
- have a HECS balance of $10,000 as at 1 June 25
- Pay off my HECS with a voluntary repayment immediately after, let's say on the 2nd June 25
- Legislation is then passed later in the year (let's say 15 August 25) and, as promised, 20% of HECS as at 1 June is written off.
In that case what will happen on the 15th Aug? Since I had a HECS balance as at 1 June 25, will 20% be credited ($2,000) and, because I have $0 HECS, will the $2,000 be refunded to my bank account?