It just doesn't appear to me to be something so tough to get right.
It isn't. That's what's so damn frustrating.
Maybe I'm just a hard ass (and maybe I wouldn't be around for too long) but I can guarantee you that if it were up to me those production tunics would NOT have been acceptable (because, to me they aren't) and ANH Luke would not be leaving the factory until it sported something much closer to what was on the prototype.
I would learn very quickly how to write and say "not acceptable", "try harder", "uh, did you actually LOOK at the prototypes?" and "do better" in Chinese.