I have noticed that the silver and gold bonuses are not really worth it!
you only get the bonus on the economy miles not bus or first points as with all other airlines.

so a first syd-bkk as silver only yields 1711 bonus points
it should be 25% of double the miles
also
if you do your 25000 miles and the miles do not credit before they decide that you are silver you do NOT get the silver bonus on the following flights.
I have been emailing them constantly for months about my bonus when arriving in DXB and departing the next day.
no luck they dont speak english