hi, without ever seeing it I'm working through all the logical possibilities

You slowed the tempo to avoid using another variation? Cool! ... as long as you're not cramming the Flight of the Bumblebee into 4 bars it probably is not too critical

The solo composer variation of the Americana series was exactly the same principle. Instead of a normal style variation, the solo was a 'mini-song' multitracked in the composer with melody riff and complete backing including a chord progression. Because it was in the composer, while playing live apc, you could start it in whatever left hand chord you were playing at that time and it would continue it's melody and chord progression from that key. At the end you just switched to the next (normal style) variation and continued playing normally, but once it was triggered you did not need to use right or left hand at all since the complete 'mini-song' played automatically for you. To start the solo variation you only needed to play one note in the left hand and sit back, just as you would to record it in the sequencer. The idea was to give you a little break for the middle eight or whatever - useful because that's what you tend to forget how it goes anyway!

thanks for the thought-provoking 'who dun it?' ... ( or 'how dun it?' )