The interesting consequence of this is that the commission rate will be a floating amount for items pegged to a fiat currency, and it will actually go up as the price of a bitcoin goes up. Here's a graph of the commission at the current exchange rate of about $77 vs if it was $200. http://32yehzkk7jflf6r2.onion/comm.png The reason is because as the price of a bitcoin goes up, a dollar becomes a smaller fraction of 1 BTC. In the simplest example, an item costing $1 would make the p term 1/77 at $77, and 1/200 at $200. Compare e^(-3/6) to e^(-1/6) to see how it goes up if the p term decreases. Also, the light gray dotted line is the (cumulative) old rate. So the rate is pretty much the same for items costing $50 to $300 at the current exchange rate, otherwise it's higher.