Hi,
SIN-VRN via RYK
I was transferring some routes from 757PF to A321-200F.
For the outbound leg, the shown payload limitation is the toughest one (as it should), ie from Shaik Zayed to Verona (2955nm).
For the inbound leg however, the limitation that is displayed is the one from Shaik Zayed to SIN, ie the limitation on the shortest sub-leg (2522nm), as I was able to check by fake-creating a SIN-RYK route, thus making the player believe that he can handle 25.000kg, while irl he can only take 20.000kg.
Edit: I did create a route to check the figures, and I'm definitely right, both legs carry around 20.000kg of cargo.