I think you will find that the 2 hole system is a way around the patent that exists for a single hole, only applies to manufacturing not modifications, one of the other manufacturers probably Preston patented a single hole set up, sure I read it on here some time ago.
I’ve had a Z12 since day one and find that the in & out set up of the 2 holes does put more wear on the elastic especially the heavier hydros, and of course more eleastic is exposed to sunlight as well so more likely to perish.
Slowly moving mine to use only a single hole or straight through…..