capt, your "annual return" is not a one time deposit at the end of the year. It is based upon trades compounding during the year.
Taking a return that is the function of a compounded calculation and then compounding it again is not correct, IMO.
You could even figure it out using your public trades. Start with your $100k initial investment, and double the return from each trade, simulating a 2X investment vehicle.
I would go to that collective2 site and check it myself, but the site appears to be down right now.