When direct purchasing game text shows "you bought X amount (product). it cost you X gold coins."
Could you add a line after that gives you the average per crate cost of that purchase? So one could verify voodoo and tech cost of purchase.
Could warehouse stores show average purchase price of good stored? per commodity.
If I buy Iron with West India on some, and Warehouse Tycoon, and maybe not used West on another purchase, I would like to know my average holding cost. This allows for trading off of current market base prices and setting fleets away from whatever the current hot trade route is.