The refueling priority is as follows:
- First, the Left/Right Main tanks, filled together to maintain balance.
- When Main is full, the Left/Right Auxiliary tanks will be filled, if they exists.
- When the Aux are full, the Left/Right on the Wing tips will be filled, if they exists.
- When the Wingtips are full, the Center tanks will be filled, if they exists.
- When the Center tanks will be filled, External tanks will be filled, if they exists.
So, it's possible those remaining tons ended up in the Aux or Wingtip tanks, but the total should be correct.