Suppose I made an EA and it lost 80% of the trades that were taken. Assuming all variables were the same, if I reverse all my conditions and sold at my old buy signal, would i end up with a system with 80% winning percentage? Just a thought, rather than making a winning system could we all make a really bad losing system and invert the criteria? just a thought.

We've ALL had this thought at one time or another. It makes perfect logical sense right? I mean, why wouldn't it work? Well, guess what? It doesn't work. Anyone who has been at this game for some time will tell you that. Take it from me, someone who has tried exactly what you are proposing, several times.

It just does not work.

Welcome to the mystery of forex!

No. There is a spread.

More than the spread, it's probably the drawdown that kills most trades. Not that the spread doesn't sting!