flight plan info
My believe is fuel tankering should be done only for operational reasons and not be driven by economic consideration.
One of those situation is positionning flights (no load).
Here you can uplift from the beginning the fuel for the 2 next flights (without having to call for fueller at the next station). You will in this case (if the fuel is cheaper at the first station) uplift much more than 1t.
The indicated information of gain or loss for 1 extra ton is then erroneous as you will extrapole from 1t to 5 or 6 or even more... but the gain is not linear...
Thanks for your contribution
Fin