The actual purchasing cost of Party A is 2000-(2040-1900) =1860 yuan per ton. If the contract held by Party A expires, the purchase cost is per ton 1900 yuan, and the cashback period is per ton 1900- 1860=40 yuan.

The actual sales revenue of Party B is 2000+(2 100-2040)=2060 yuan per ton. If Party B's contract expires, the sales revenue is 2 100-60=2040 yuan per ton, and the actual saving is 2060-2040=20 yuan per ton.

I hope it helps you!

60 yuan storage fee shall be paid by the seller to the delivery warehouse and borne by the seller.