I inquired Jade in NYC about Feb. fares on CX from JFK to SIN last week. It was just above 800USD.

I realise this fare is more expensive than the one the original poster got. But this is K fare, mileage eligible with CX's FFP AsiaMiles, and is valid for six months. You can also have stopovers both ways and date changes are permitted free of charge except the JFK-HKG.

I was a little surprised about Feb. fares ex SFO to TPE, which was about 660USD with the same conditions....