Is it possible to change the octave setting on only one part of a shift on MX88?

The parameter you are looking for is called NOTE SHIFT.

Here’s what’s causing the head scratching... TRANSPOSE and NOTE SHIFT probably are words used in the common language to mean the same thing. But in the synthesizer we create the following difference: TRANSPOSE is used to describe changing the key as a function of a keyboard transmitting, or note data of a Sequencer track... but TRANSPOSE is a function of “transmit”. We describe NOTE SHIFT when referring to reception... as in the synthesizer tone generator receiving a message from a keyboard...

So the two things accomplish the same thing with the following difference... if you TRANSPOSE the MX “Keyboard” it will affect what goes Out via MIDI. Meaning everything moves. However, if you go in and NOTE SHIFT the individual PART, only that Part is shifted. Nothing connected via MIDI is changed. And physically your SPLIT POINT can remain on the Keyboard where you want it!

So it is a “PART” parameter you are looking for, not the front panel (Transpose) button... which affects the keys.

Call up your SPLIT
Turn OFF the [SELECT] light so you can see the names of the two Voices assigned to Part 1 (top) and the split Part 2 (bottom).
Move the Up/Down Cursor so it is flashing next to the Part you want to Shift
Press [EDIT]
Using the Up/Down Cursor to select “02:Part” > “Enter”
Select “01:Play Mode” > “Enter”
Use the Up/Down Cursor to find “Note Shift”
Each step +/- is a semitone; 12 semitones is an octave.

Use the numbered front panel buttons to switch from Part 1 to Part 2 shile viewing this parameter, so you can adjust it’s NOTE SHIFT, as well.

Press [STORE] to update your Performance.