Originally Posted by SingaporeDon

One risk of taking SQ25 JFK-FRA and then the VTL SQ325 after 12 hours in FRA is you will need a PCR test done within 48 hours of the SQ 325 FRA- SIN flight and depending on when you did your PCR test in USA before you take the SQ 25 JFK- FRA flight, you might not catch the 48 hour window for the PCR test before boarding SQ325 in FRA.

To avoid the risk I ended up buying East Coast to LAX connecting to SQ 37 VTL LAX SIN flight for DS in PE to protect and will try to waitlist for miles upgrade but chances are slim.
But may be the load in PE on SQ 37 might be light given the type of plane as discussed in another thread here so he might be OK In PE too