I found that an interesting observation and grabbed my F95R and NeOn UL (don't have a Zero) to compare. I traced their movements on a sheet of paper and indeed the 95 swings only 10 degrees until the detent ball hits the locking ramp edge while the NeOn swings 25 degrees to the same point. In practice, for the way I disengage and close, that presents no problem at all as the diminutive Neon flipper tab hits the corner of my thumb well after the ball is riding the tang. I can see how one could choke up further forward on the NeOn's lock bar and cause the blade ramp to catch on the detent ball, but I can do the same with the F95 to get the ball to hang up as well. I seem to just naturally disengage a bit further back--maybe it's just my short thumbs.
I've never noticed any of my Shiros including the little guy being a problem with this issue and it's one of the reasons I like my Bears so well. My Hinderers, on the other hand, mostly all can present some disengagement difficulty with their long hooked flipper tabs. If I don't very deliberately stay back on the lockbar, the ball hangs up and impedes a hitch free closing. As much as I enjoy my numerous RHKs I do find that characteristic annoying. I generally have more disengagement issues with frame lock flippers than trouble opening, given my thick, short-fingered hands and arthritis. That's one of the reasons I've divested myself of most of the ZTs I've had given their usually stiff lock bars.
