Thanks again for the responses. SQ called me back to run through the combination and managed to price it.

I'm a sucker for a good deal and this is where is gets a little frustrating: BNE-SIN-NRT-SIN-BNE on their website in premium economy, it's $1700. B, E, Y economy is $1600. Naturally one will be drawn to PEY. But as it turns out, only 2 out of the 4 sectors are in PEY, the other 2 in Flexi-Saver. Through customer service with SQ, PEY for all 4 sectors is >$2K. Why can't that be on the system in the first place!