I'm fairly sure this is just an exercise in gov't waste. They don't want to lose the budget, so they buy unseemly amounts in bulk to make sure they use up those dollars, IMO.
Im not 100% sure, but usually you don't use JHP rounds for target practice. Those are.combat rounds.
Possibly, but there are more creative ways they could spend the money without drawing so much attention. Note to self, get job with DHS, unlimited practice ammo