Thanks for all the replies.

Completed the trip yesterday and 40kg was indeed my entitlement due to *G. But thanks to suggestion by alwaysaisle, I showed my boarding pass for same day international connection and the JPY4,500 charge was waived !

But the experience on arrival & checking in at HND was something else…the transfer fm T2 to T3 was a PITA with Keikyu line. Not to mention AA’s check in process was a strict 2 x 23 (not 22+24kg). I had to repack my check-in luggage to comply.

Will definitely stick to same alliance going forward !