All ammo trucks and vehicle ammo crates has not enough ammo capacity to even fully resupply ONE vehicle. One truck can at most refill 100 rounds of 20mm cannon rounds for the comanche, or maybe some 6 rounds for tanks. This suggests that it is the ammo trucks capacity which is the problem, and not the cost of the individual ammunition pieces.
In my opinion you either have to increase the the ammo trucks/crates ammo capacity by a factor of 1000000 or just completely scrap the whole ammo capacity and cost thing. This would clear up computing power and spare the multiplayer servers from running scripts to be able to ressuply vehicles, further improving performance.
Refueltrucks too have way too low capacity to refuel vehicles, needs to be increased by about 1000 times.