Therefore if the aircraft flew faster then it MUST cover a greater distance (+/- 20 mins worth - see a previous post).
No arguing with that, for the same time period. But...
60q of fuel at x, consumed at 15q per hour equals 4 hours' endurance after x.
Same aircraft but with 80q of fuel at x, consumed at 20q per hour still equals 4 hours' endurance after x.
They'll run out of fuel at the same time (A) but won't run out of fuel at the same place (along the arc plus post fuel-exhaustion 'glide').
That's why I guess a change in understanding of FOB at x is changing the estimated impact location.