I am trying to book 3 (2 adults & 1 child) business class reward flights on SIN-GRU. However, I noticed that I will always be put on waitlist.

But when I tried to book 2 business class reward flights, they can confirm my booking on the spot.

My question is how probable will 3 business class reward flights be confirmed after being on the waitlist?

Any chances at all for me to book 3 business class reward flights (to any destinations on SQ) without the need to be on the waitlist?

Does SQ do this on purpose? Limit 2 business class reward flights per booking?

Just curious.