They're evidently not doing a very good job of not calling it an arranger because that is in fact what they call it on the Casio web sites (there are many). Here's one of them: http://www.casiomusicgear.com/products/menu_mz-x/mz-x500

Why do you keep posting about this? I have a theory but we're supposed to remain civil here so I won't say it. But I will say that if the explanations already given in this forum for why Casio is de-emphasizing the arranger nature (not completely surpressing it, otherwise they wouldn't have officially called it that in their literature) aren't convincing you should ask Mike Martin or his counterpart in Europe directly.