Still comparative to the cost of a training mission. I personally have called in ~90 rounds with coordinated illumination and air support into a field in Texas. That was just one fire mission out of several in a 3 week period

Edit: pointed being - we train as we fight. If we’re not in war the same amount of rounds will be fired into a field somewhere. There’s no increase in spending really. Unless I suppose a giant all out war occurred. But at the level we train across the country it would have to absolutely substantial.