A close listen to the recording suggests two things: 1) there is some sort of core voice leading going on that is more or less the same throughout, and 2) Herbie Hancock and Chick Corea are each adding their own alterations to these core voices, and change these each time. So, without digging into the rich alterations used by Corea and Hancock, I think this is a close approximation to what they were working with:
(To download MIDI file click here.)
To hear the passage I listened to for this, begin at 4:57 of this video.
I'm not especially happy with the 4th chord, but I think the others are pretty close. I'm very interested to hear what other people think. Post a comment!