The airline is building in some extra fat in case of delays during turn around.
Keep in mind that it is a new type in operation. The 700 is from a technical viewpoint only 54% similar to a 200 (the cockpit is 89% hence the common crew qualification) and the ground handling personnel therefore may require some extra time to get to grips with the aircraft. Sector and turn around times are bound to be reduced as the operation matures.