That is correct: once you have purchased your VAS or STW on the...

That is correct: once you have purchased your VAS or STW on the market, the only fee you have to pay is brokerage when you buy. (Theoretically you would also have to pay brokerage if you sold the units, but of course you wouldn't do that...)

The management fees are included in your return (i.e. 0.286%pa for STW or 0.27%pa for VAS). The reason everyone (justifiably) stresses the significance of these numbers is that management fees COMPOUND over the life of your investment: therefore a small difference in management fee per annum translates to an enormous difference in your total return over a few decades. This is one of many reasons why I (and others) prefer low-cost index funds over retail managed funds, some of which charge north of 2%pa as a management fee. Those funds need to achieve returns, each and every year, of ~2% over and above the index just to MATCH the returns of an index fund.