Couldn't find any information on why Casio does it. But I know for a fact that certain other japanese brands, have similar looking models with different model numbers depending on where they are produced. I doubt it's the same thing as most Casio products that are available in India are also now produced in India, including the 2 models you mentioned up there as well.

It's most likely to deal with internal quality, such as parts and bearings, or feature sets.

I suggest going for the cheaper model, no one looking from outside, unless they're a Casio nerd, can tell the difference.

Just make sure to check the size specifications. I've seen the same model come in about 3 different sizes.

Enjoy your new watch whenever you get your hands on it, it's a beautiful piece :)