I purchase a lot controlled item from a supplier whose price at the time is $1.40.  Because this is a commodity type item (aluminum bars) whose prices fluctuate and our customer updates their standard costs monthly with the the CURRENT price of the material from the supplier ($2.00), when I do a return for credit, I get a financial transaction that shows the difference.

But how do I notify/charge the supplier for the 60 cents difference so they can “pay” me?  The optimal way I think of this is PERHAPS use cost per lot batch but the customer doesn’t want to use that; opting for a standard cost per part.