JV1080 could receive lots of data in a short time, but at exactly the same time. That's why you could try to edit your song and set the notes just a little out of time. In MIDI protocol, each note is sent as a "word" of 1's and 0's, and too many commands at the right time can cause problems. It is therefore not the JV who is to blame, but the 1980's MIDI standard!