…it occurred to me that, rather than changing the behavior of the extra fuel drop-down (even via a checkbox), it might be easier to just implement a basic “tankering” feature that automatically loads as much fuel as possible without having to reduce payload for MTOW and MLW?
I kind of like the checkbox method better. I think it would be more flexible, rather than an all-or-nothing maximum tankering option. And maximum tankering would still be possible by simply checking the box and entering a large extra fuel number.
It’s on the to-do list but it might be a while before I can add this however.