Where Minimum Cost doesn't equal Maximum Profit

I thought of some situations where this might apply, although I'm not sure of the specifics.

I would think that when there is some kind of cap on total cost, like once your order reaches a certain point, then the cost is capped and can not go any higher. This would make your cost higher than the minimum but there could be a point of order amount above that where it becomes more profitable to buy that amount even though the cost is higher than the minimum.

I would think this is only really possible when special constraints or features affect the costs.

-Mark Brislin