I may need glasses too. Having read and reread your question a few times, I struggle to understand your question fully. I can only get that you want to go from PER to USA. Do you want to use Krisflyer or Velocity points? Do you want to fly on Singapore or Virgin metal (aircraft)?
Which ever FF points you intend to use in this case, return tickets cost the same as two one ways. Only think with Krisflyer is you get a free stopover if you book return tickets.
What class of seat are you planning to redeem? For 1 passenger?