An SQ redemption using Amex MR points would be ~46,250 Kris Flyer miles which is 55,000 - 15% online discount.
If you did not have any VS miles and the redemption needed was 55,000 miles then that would be ~42,300 Amex MR points.
For travel after 1 April that will become 50,000 miles - 15% discount = 42500. Easier to book SQ through SQ than through VS, which I tried once, and it was a PITA just finding out what availability was like. That was nearly 3 years ago now though.