IMO you are right to be sceptical. I think the complete history of Roland regarding arrangers has been BASED on Roland Europe and began when Roland bought SIEL and changed it to Roland Europe. With accordions it might be even clearer, as this traditional instrument has no "cultural basis" in Japan. For arrangers, there is some hope, as the GW8 and Prelude were developed in Japan. But I certainly see the danger that the arranger section could be abandoned, of course depending on the sales figures. These don't seem to be encouraging for the BK-9 at least (up to now only 4 reviews at the Thomann store, unfortunately I see a lot of BK-9s returned by customers; the BK-7m seems to be quite popular however).