People are always asking me how to make indicator in the EA, because these calculations are basically this
And I always explain that the best is to get signals directly from indicators. The difference is that indicators (if well written) does not recalculate on every tick, while in the EA this is hard to make, especially in EA builder.
Anyway, I finally added this field, which allows us to calculate some things - http://prntscr.com/9egr7i - but your scenario (to detect that only 1 crossover happened in the last N candles) is more complex and specific and I don't feel like I want to do it, at leat not somewhere in Condition 
Otherwise the logic would be to make "for" loop and count crossovers from below and from above and then to pass only if this count is 1. If the count is 2 - break the loop.