Used SQ chat today regarding my NZ codeshare SIN-BKK sector on SQ metal. Live agent could offer me seats further forward, but this required a $22 fee. I declined as this I am currently only 10 rows further back to that offered. I’ll try again at check-in.

Seems my flight under the codeshare is in a vey cheap SQ fare class (it is NZ ‘S’) , but can’t see what that maps to on SQ.