If transports are empty, their movement cost should be greatly decreased.
A simple formula can increase the fuel cost for each slot used.
This would remove hesitation from upgrading
CBE, which was a large reason fuel costs were removed from most mods in the DN update.
This would primarily help with shipment organization in YS, and it would fix the CBE bug to preserve hydrogen.
The bug allows removal of CBE with a full ship to move around at the lower cost while carrying full capacity. If movement cost were based on how much is being carried, it would be more intuitive and prevent exploitation of such mechanics.