If I was doing it, I would go and book with SQ, the reason why is that if you phone, the call might go off to the Philippines, ...
No sleigh to them, but I would prefer to do things online, less errors.
You will still earn points and SC (?) on the flights flown, and you can also get the seats you want.
If you book with VA online (Au to Sg), then other ways from Sg to Hk, you don't get the chance to get eg, window seats or up front seats (behind J)...
I booked online for my flight from Au to Nz, on Air NZ, just so that I could have window seats.
It (the system) would not let me check in online, so I had to front up to VA in ADL in person.
Just by luck I got window seats all the way.
Booking the return online with QF flying EK metal, I have also got window seats, (touch wood-all the way window seating).
If you love window seating that is!