OAS styles are primarily organ styles, if you want arranger styles you will need to add the OAA (Open Art Arranger) software. (In case you are wondering 99.9% of OAA users don’t use Yamaha styles, (Even though it can play them) preferring the OAA styles)
Coming from an organ background I also have never personally been impressed with the Yamaha styles. (When you listen to live groups and bands regularly like I do, Yamaha styles just don’t cut it)

Bill