Package tracking

It would be ideal if ShipStation had a way of tracking the inventory of shipping packages. We've set up all our pre-sets with the box sizes, if there were another field for us to enter a starting inventory of those boxes, and decrement every time an order calling that pre-set were processed, that would really help to track the boxes. Since the sold configuration of our product inventory can vary, we always have to make the decision as to which pre-set to pick at the time we are processing the shipping. I know a workaround is to create shipping boxes as "products" and use ShipStation's regular inventory management for this, but we don't exactly want the shipping box to appear on the packing slip, our customers would think we're charging them for the shipping box. Thanks