Well, you made no implication on what you wanted the rewritten manual to reflect, only quoting a passage defining how the native keyboard sends monophonic aftertouch messages. No disrespect was inferred.
The manual does in fact state the OB-6 responds to polyphonic key pressure, check page 72 under Received Channel Messages. Since this is a received MIDI message and not something natively generated by the built-in keyboard, the MIDI Implementation section of the manual is the correct location for this information. It is not incomplete.