Igor,
You assume that a currency will move in a linear fassion up or down ???
ie - you assume that it will exhaust its up range of x and go down...that is like picking tops and bottoms..........
You know very well the crazy currency movements!!!

I dont think that this approach will be successful in the long run.
And to some extent you contradict your FXIGOR approach with this approach, so with all due respect I am a confused by your FXIGOR approach and this one.