Perhaps instead of trying to fix what you are looking at, you may want to figure out what you are looking through...
If you think you can trade a mechanical system (or any other for that matter without DDs you are dreaming. But, yes, I agree if the system seems to be 'falling apart' then you may have problems with changing market conditions. My point is you can't assume that your system if failing the first time you have a few consecutive losses. gs