SQ 21/22 are operated by the all-Business class aircraft, the A340-500. These flights' award seats may only be redeemed using SQ's own FFP, Krisflyer miles. Thus you will not be able to use CO miles to redeem on these flights.
Even if you want to redeem them on Krisflyer miles, these flights need more miles than usual...
A oneway award from EWR to SIN on the A345 alone, will cost you
381,000 miles. That's ONEWAY !
See info here:
http://www.singaporeair.com/saa/en_U...ardCharts.pdf?