When changing servers

What happens is that I play both on LAN and NA (this is below level 30), and when I switch from NA to LAN puts me on the launcher that downloads approximately 11mb, this every time I make the change, but curiously how much it is (from LAN to NA) Absolutely nothing happens, my doubt is because this happens, because every time I change service it is as if I update the game. Does this really fill me hard drive on my PC or is it just an error and the files you download overlap and the size of the game is still the same?

[sg-janna]