Don't forget to include the fee's from an unstable method of exchange (bitcoin) depreciating or appreciating between the times you exchange it for USD.
Bitpay assumes the volatility risk for customers and merchants, and charges at most 1% for their cheapest platform, so none of this is really an issue - is it?
Bitpay is when the customer pays in bitcoin. But to get bitcoin you still need to exchange for USD somewhere. And that's where the cost of exchange risk comes in.