The pressure controller does not have a throttle range, because there simple is nothing to throttle only reduce.
The term throttling range is not limited to pressure or flow. For example if a proportional HVAC system is controlling temperature and the valve controlling chilled water to an air conditioning coil is wide open at 75 degrees and closed at 72 degrees then the throttling range is 3 degrees. In this case the error is not necessarily unwanted. A PID control system might keep the temp at 72 degrees all summer but it will use more energy because it will take more power to keep the building at 72 during peak summer conditions when the proportional only system would be at 75 degrees. At 75 degrees all summer then some people might be uncomfortable when outside temperatures are below that.