I wouldn’t obsess over the changing amounts, that’s how it works. They have an allocation of money and a weighting for each constituent. When authorised participants (institutional investors, mostly banks and funds) participate in “creation” events - this increases the exposure of the index, and creates more ETF units for trading as the same time. When the reverse happens, “redemption” events, they burn some ETF units (via the participant first aquirijg them) and sell out underlying constituents.
Basically it will go up and down all the time and institutions behind the scenes are making most of the money.
The only time anything significant will happen is if the ETF is wound up, a big creation event happens (rare) or rebalancing causes a constituent you are interested in (ASN) to either have a big purchase or sale - that happens only quarterly or whatever depending on the ETF.
