260+80+40+290 = 670 fuel. With OKW's reduced fuel income that's equivalent to 917 fuel.
Yeah, uh, if you are facing down a KT + JT combo something went wrong somewhere on your end vis a vis map control.
Just stop your fuel math. After 2 schrecks and few mines you have nothing to spend ammo for (just nades but 15-19ammo/min is enough for them) -> fuel conversion all day long.