Correct the Diskcover5 is a none arranger. The idea is that you can load in a midi file. Decide how many bars of the midi file make up the Verse...Chorus and other parts the midi file uses to build up the song. Any of these parts can then be assigned to buttons provided. This enable you to loop back and forth to different parts of the song that you would be playing live the melody part to.
This is a very clever feature and could possible be an advantage if this type of thing was added to the next new Roland Arranger in 2003.

Graham UK