Spalding keep in mind the difference between the Performance mode on the synths, and the registration set ups on arrangers.

Synths have (16) part Peformaces at your finger tips. With the XS for example all 16 parts will be available at a button push where as with the arranger you'll have to go though banks as there is only a few slots within each bank.

There are work-arounds on arrangers though. You could create a seq template really on the PSR's and set up 16 part performances that way. You can save multiple seq temps to the song memory, and those parts will be available on demand as you can use the softkeys to access each part on the fly.