The only thing a fighter should be able to dump is ord.
Me? I think the ability to take up anything less than %100, especailly in fighters, is about as bogus and far away from "realism" as one can get. People talk about the desire for accuracy and realism... well removing the ability to take %25, 50, and 75 fuel in fighters would be a good start. Or, at least make it so drop tanks can not be carried without %100 fuel.
Then, make it so when the fuel depots are destroyed at an airfield, he max of %25 can be taken in fighters.
Or... HTC could just make the burn multiplier higher at 2.5 or even 3. That would change things drastically.