I think we've rehashed the size/scale so many times over the years everyone should know by now what happens to cause differences in various figures. Too often no matter how attentive and conscientious (or the opposite) a maker might be with the current vast distances (across as many as three continents in some cases) involved in the process of sculpting master figures, making the molds to proper (or improper) size, then casting masters or test figures - getting them back to the maker for check - corrections - and the expense involved (not to mention the pressure to get every new set out yesterday (!!!)) in this process stuff happens to screw it up.
Oh, for the days of the big toy companies like Louis Marx & Co where the maker had total control of the manufacturing process from start to finish.
As the man said, "S[tuff] happens!" It's a fact of life. We live in an imperfect world.
I am 100% agreement with Alan and don't trust Italeri or Zvezda (they're pretty much out of making the little guys so it's a moot point anyway) without checking PSR - good advice all around.