Unhedged items would have a consistent commission, because the vendor gets whatever BTC was put in escrow. Not sure how hedged items work. They could base commission on the BTC at the time the buyer submits the order or the BTC the vendor gets when the buyer finalizes. List all your items in BTC. Yeah, but it's somewhat deceptive. You want to look at the difference between the blue and black line vs the difference between the black line and the bottom of the graph (which is below zero because I was lazy). That's the percentage difference between the two exchange rates.