Just found the answer to my question. It seems that in the document "P6_OB-6_MPE_instructions.txt" there is a clear explanation of what all the Third Globals functions are:
Basic MPE operation:
MPE is turned on/off by using the MIDI Channel global. MPE is one past channel 16 and takes over the channel assignments completely
Works with 6 voices on MIDI channels 2-7. It does not work with polychain.
When MPE is on…
CC 74 is now overridden and is routed via the Y-Axis destination global. The behavior is controlled by the Y-Axis Mode global.
Program pitchbend is now overridden by the Master Pitchbend Range global
To reach 3rd global page: hold ‘Bank’ and hit ‘Global’
0: Master Pitchbend range from 1-96 semitones (default 2)
1: Voice Pitch bend range from 1-96 semitones (default 48)
2. Y-Axis Destination: Cutoff, PW1, PW2, PW12
3. Y-Axis Mode: Unipolar, Bipolar
4. Vintage On/Off
Master pitchbend now overrides the program pitchbend when MPE is on.
Voice pitchbend responds to pitchbend on each channel, 2-7
Y-Axis destination should be straightforward.
Y-Axis Mode: In unipolar mode CC74 affects the destination by adding 0-127, in bipolar mode it adds -63/+63 with 64 as a the ‘0’ point