I purchased PX-560 a week ago. I could not understand the difference between Acoomp and Auto Harmonize features. Both look alike to me. Can some one please elaborate how to use Auto Harmonize. Also I could not understand the types that we can select and what they do in this feature. Whenever I am making it active, I observe that the Accomp button is glowing and my keys on the melody side start to sound weird (not like the instrument that I have selected). They start sounding like a chord . Is this a problem ?