I wouldn't expect great repeatability from a system with 2 moving jaws. 0.01mm is pretty good IMO, and better than I expected, I figured at least double that or more. Even a Kurt vise can vary that much depending on how much pressure you exert on the handle.
Centering vises are typically meant for production, working from the center of raw stock, assuming you have excess material to spare around the edges. A profile, then flip into soft jaws and face type order of operations. I work like that quite a lot, and would love to have one of those "5 axis" type vises with integral talon grip jaws, but they sure are spendy. I can't bring myself to spend that kind of money though unless I was making money from it. The Import ones look so shittely made they don't look like they're worth taking a chance on, and the gemoetry of them doesn't even lend themselves to treating it like a kit, and grinding it all true. Have thought about making one every once in a while, as they aren't that complicated. Would be nice in a 5" version. and would fit the work envelope of the Tormach pretty good. Someday.....