Frostengine,
You might want to look at volatility. I am seeing an increase in volatility lately, evident by the vix and the increased in daily ATR. Now a 2 handle move in the SnP could happen in 30 seconds which was a 1% outlyer a few months before. Now it seems that we are getting a 20 handles range everyday and a 2 handle move in a blink of an eye. If you still use the stop like a few months ago, i think you could get stopped out easily.
Also, the market has also become more whacky than before. Up and down up and down, take out the high then take out the low only to take out the high again, which didnt happen a few months ago. Few months ago, the advance was very orderly, not the case now.
I guess u might want to look at your system with vix as one of your variables.