Just a quick note, if you don't like the posted ROI, just ignore it. Many readers will find it useful.
However, it is not a very good indicator for "lumpy" betting where some bets get resolved in under 3 hours and some others (futures, RSW) take up to 6 months. Better would be to compute the Internal rate of return (IRR) or the XIRR (non-periodic bets, function is in MS Excel) which requires iterating to a solution.