How long does it take the average Neti Pot user to flush out their sinuses?

I used the Neti Pot for the first time and found it interesting that it took so long--about 10 to 15 seconds for the liquid to begin to flush out the other nostril. And then it only drips slowly. Is that typical? It also seems to take longer going one direction that the other which seems weird to me. If the sinus is open to allow drainage to happen in one direction, why wouldn't it be open the other direction as it takes the same path only in reverse, right?