Not sure how it works Max, but I think the second it grabs the other side would grab as well. Not that it matters much how it works, they work very well and grab withing 100mm of pulling on the cord and they never slip and I have been doing them this way for a number of years now
Even if only one pawl is doing most of the work gripping the cup, it will all average out as far as wear and you'll turn over the engine in the end.
