If I had known this would happen, I would have saved so much $$ by not up-faring to P class for my last EWR-SIN roundtrip

SQ doesn't just have R fares...it also has the super-cheap "two-to-go" R fares when you buy two tickets. When I checked last SIN-EWR in PE was $1500, but two tickets were only $2000 and also booked into R. If you need to go to Singapore and somewhere beyond, that is an amazing deal for AS EQMs and RDMs (esp. if you have status).