Fibs is just another indicator to use, it is by no means 100% profitable for any currency, if it were, then.......
Whatever indicators you use you will always need to factor in the underlying ever changing currencies economics, this has become even more apparent since 2008 due to the world economic downtrend.
Even then you are still at the mercy of short term speculators which as you have seen have/are causing mayhem for the EURO.
I dont see the point in back testing any system apart from making sure it is actually making some kind of trades. The past has already happened, forget about it.
Trying to predict the future based on past data is fundementally flawed.
Scoobs.