Buying Virgin Australia Marketed Tickets on Singapore Air

[PP075]

Due to recent changes to earning Status Credits on VA‑marketed flights, including a 50% cap on partner airlines, I need to book my Singapore Airlines flights to Asia through Virgin Australia to retain Platinum.
When booking through VA, I can only select Flex or Business fares (when available).
I’m curious about the options once a VA‑marketed, SQ‑operated Flex fare is booked. Can I select Economy seats with extra legroom using Singapore Airlines reference on their website and pay SQ directly with a credit card?
Can I upgrade to Premium Economy through Singapore Airlines, select a seat, and pay the fare difference with a credit card?
I’d appreciate any insights from anyone who has tried either option?

 

[Rayesfeg]

Can I upgrade to Premium Economy through Singapore Airlines, select a seat, and pay the fare difference with a credit card?

No. You cannot upgrade your ticket on this Singapore airlines flight.
From the SQ website "Regardless of your upgrade option, your flight must be ticketed and operated by Singapore Airlines.".
As you will be booking through VA, it will not be ticketed by Singapore airlines.