Hi Bruce,
The 'Pitch bend calibration' is used to tell EigenD what the pitch bend limits are of your plugin, ie. to calibrate it for each individual plugin so that EigenD and the plugin can agree. The actual key pitch bend range when you move a key up and down is set in the scaler agent (key bend range).
While it might be different in Garritan JABB (we don't have a copy so we can't check), we've never seen a plugin that has fractional maximum pitch bend up and down settings. However, if your plugin for instance has limits of 2 semitones, setting the up and down calibration to 1 will tell EigenD that it has to spread the pitch bend values between one semitone up and down. Now, since the scaler defaults to a pitch bend of 2 semitones in the factory setup, it will reach the maximum MIDI pitch bend value when you're half-way the key's roll inclination (the scaler sends out half a semitone half-way, but that's set as the maximum in the plugin calibration). However, that maximum is then in this case interpreted by the plugin as 2 semitones, ie. a full tone since that's what it converts the pitch bend values to.
Can you please check that this corresponds to what you're seeing. We know that it can be a bit confusing, but sadly there's no real way to make this easier since there's no way to tell what those pitch bend values are set at in the plugins.
Best regards,
Geert