Just a thought, but it occurs to me that you could two sets of changes programmed as shots, one with chords 2, 4, 6 and 8 of each bar which once generated, get moved to a convenient empty channel, (say the soloist).

Then you offset the playback of that channel that by anything from 50 to 60 ticks behind, before generating chords 1,3,5,7 on the piano channel. The amount of ticks depends on the feel you want, syncopated or straight.

Hard work, counter-intuitive and bothersome?.. sure it is...Sometimes it works ok sometimes it just sounds ...what it is ...which is 'computerised'. But it could be ok for some sparing use.

Will need to do for now, but here's hoping it wont be long before 8 chords that actually sound as eighths are supported.

Regards

Alan