Well, under "on Tick" any blocks are doing what they do in the current moment. Conditions are checking things now. Of course, old data can be used, but it is used at the moment. If you know at which candle the crossover must happen, then you can detect it for this candle. Otherwise, of the crossover can be anywhere... well... why not just using > or <, because if line A crosses over line B at some moment or candle, then after this cross line A is > line B for sure.
