A word of caution ... never assume Singapore Airlines will recognise miles booked in 'V' or 'W' class in a Star Alliance carrier.
If you book in 'V' or 'W' on Singapore Airlines, no points will be credited.
If you book in 'V' or 'W' on Thai, Thai will credit at the rate of 50% to their scheme - Singapore will not credit anything.
As I understand it Asiana will credit at the rate of 70% to their own scheme. United may well recognise the miles - No idea what Singapore Air will do.
It's a real pain. Love Singapore's service in the air - really struggle with this sort of stuff - Krisflyer do a pretty ordinary job in publishing the rules. It would be great if Star Alliance could standardise earning conditions over all partner airlines, or failing that if Singapore were more proactive in publishing the rules. Ho Hum.