You are absolutely right. This was info" I took from www.canadianinsider.com.It appears that they did not differentiate between US$ and Cad$ buys.
Thus the difference was NOT $2.64.G.Riley's buy @US$5.83 converted at 1.28 equals Cad$7.46 versus $8.47 which is a difference of Cad $1.01.(On May 5th the stock did close in Canada @$8.47)