Rikki it's been a couple of years. But I'm pretty sure that the style architecture, the detailed style control parameters and chord fingering modes as described in the manual were identical to Yamaha's. Too much so to be a conincidence. So it's either blatant commercial piracy, or Medeli is licensing elements of Yamaha's OS. I wouldn't be surprised to learn that Medeli can use older (Style File Format 1) Yamaha styles. My point is, why not just buy a gently used PSR?