When they have to lodge form 604 "notice of change in...

When they have to lodge form 604 "notice of change in substantial holding" is related to how much their holding changes. I was looking for the ASX rules, but surprisingly did not find them within a couple of minutes on Google.

So, this is my best guess, not a statement of fact. If they own greater than 5%, they have to announce every 1% increase or decrease.

Between 0 - 4.99%, no notice required. Exceeding 5% for the first time requires "notice of initial substantial holder"

Falling below 5% requires "ceasing to be substanial holder" then they can do what they like below 5%.

DYOR, just my observations.