The "basic strategy" performance improves when commissions are added. My apologies if this has been posted before. I searched and found nothing.
1) Without commissions:
Jan 04 2011 - Oct 17 2014 Daily 130.0%
2) $10 per trade -- set_commission(commission.PerTrade(cost=10.00))
Jan 01 2011 - Oct 17 2014 Daily 144.63%
3) 0.01 per shr -- set_commission(commission.PerShare(cost=0.01, min_trade_cost=None))
Jan 01 2011 - Oct 17 2014 Daily 139.83%