food consumption is related to time and not distance.. indirectly distance = f(time).. .. lets leave it that.. i remember transporting stuff from tuscany to upper lorraine with lvl8 relief station

also the time thingy works like a rainbow-deterrent .. 1 worker +99999 archers will reach the destination at workers (minimum) speed but still.. the 99999 archers will consume at the same rate and hence, the inflated food requirement for the mission