I think you are right here.

There are examples of B. jaina without the FW white discal spot.
https://www.ifoundbutterflies.org/me...rjar_aa295.jpg



The underside of B. anadi is purple-washed, more noticeable on the FW.
This gives it a darker ground colour.
https://www.ifoundbutterflies.org/me...438f16cf-1.jpg
https://www.ifoundbutterflies.org/me...94141dc2-2.jpg



TL Seow: Cheers.