You know, being that I'm not the world's supreme overseer of elevator regulations nor am I the plenipotentiary commissar of floor regulations, I didn't make these rules. Different countries have different beliefs, cultures, traditions and religions and for them numerology plays a huge role - not just in building regulations, but in daily life in general.
Chinese normally rely on numerology to determine auspicious days to open a company, to get married, to bury the deceased, and as far as they're concerned, they frankly don't give a rat's ass what number precedes the other. It's the symbolical value of the number that's important.
For South America, the situation is different. They don't care about the floors per se, but the function of the floor. That's why they give names to the first few floors, as they perform certain "functions" - you know, like the ground floor normally houses a lobby (which some countries also denominate what you consider "floor 0"). And if you don't have the mezzanine denominated as such, then people won't know there's a mezzanine.
Finally, about my superstition comment - read it again...
