All about the Roland Jupiter-series

Could someone explain UNISON mode a bit better than the manual? As I 
understand it, in SOLO mode, the keyboard is in single-trigger mode 
(envelopes are not retriggered with a new keypress) and the Jup acts 
like a mono, single-trigger synth. In UNISON mode, all 6 voices are 
piled on top of each other, but if another key is pressed, it, too 
sounds by "stealing" a voice from the stacked key (the 1st key 
pressed, I guess, with 5 voices, the 2nd key with 1).

Here's what I don't understand. If I am in UNISON and press and hold 
a key, and then I press another key, the two keys sound but the 2nd 
key sounds in single-trigger mode. If I press a third key, the third 
note sounds in multi-trigger mode ( a new envelope is triggered).

Now if I lift all keys except the first and try again, all subsequent 
keypresses sound in multi-trigger mode.

Its like it "misses" the multi-triggering the first time around, but 
then "gets it" once the 2nd key is released and new keys are pressed.

Tried this in UNISON+SOLO with same reult. The manual is very unclear 
on this, and so is the Keyboard Report review on this, circa 1983.

OK, is this normal, or does this Jup need a service fix?

Thanks to all...

ja
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On another subject, why do many reviewers seem to state that the 
split point on the JP-6 is fixed, when it clearly states in the 
manual how to change it? The split point is not programmable, so 
maybe this is what they mean't to say?