Originally Posted by Maride

It is due to the exchange rate. Is hard to keep up with the rate and even though recently it has been almost even most of the time, they make it a flat rate. If you use a credit card in Canada (I do often as I live near the border) you get charged in Canadian funds but you end up paying the conversion to US funds, depending on what was the rate that day. I like it better when the rate is the same.