Not sure if it is a bug or math doing its work as designed and the stats are just working against it but better Engines, especially HTE need more fuel to take off or land than a FSE.
A HTE has both more thrust and higher fuel efficiency (thrust per fuel) so even with the same thrust profile as a FSE it should need less fuel, but because it has more thrust it should need even less as it should get off world even faster.
My guess is that it is because engines burn for a set amount of the starting / landing segment time and the landing segment is only about halved so the burn time is too, but because the fuel consumption per second is four times as high for a HTE (producing 4,5x the thrust) compared to a FSE the total fuel used is about twice as high.
So one solution would be to bind the take off time directly to thrust to shorten the take off time for HTE to 1/4,5 or less than that of FSE (respecting g limits of the hull/crew but then mathing the fuel usage down too).
FSE:
HTE:
Found a even weirder one:
HTE:
FSE:
config:
There also seem to be other components to it as a full HCB with FSE needs less SF than a full WCB. Both LHP, FSE, QCR, SSL, MFL:
HCB:
WCB:
(reported 6 months ago here: Discord )