The whole thing about playing an arranger is to "ARRANGE" the playing as to sound like more then one. This includes using all the sounds & articulate them in a manner in which they are prescribed to do in their real performance state. A good arranger player is more then just a keyboard actuator & must study how each sound operates and fits in the mix with Styles & SMF, etc, etc, ...multitasking is an understatement when properly playing and arranger KB.