Hi ArunaBandara,
I have got an s750.
From default I can see that the Pitch Bend in all voices gives +2 semitones.
I couldn't find a way to change this to +1 semitone by default on my model.
So to keep the +1 semitone(and not 2 semitones),
I press Direct Access and press the Pitch Bend to call the Mixing Console to change the pitch bend semitone and save it either at the OTS voices(as a new user style) or on a Registration.
Maybe there is a system function on your s910 for the pitch bend range for all voices?
Have you checked there?