PT100 weidmuller transducers output
The difference is not in the PT100 but in the use of the transducer. The output of the transducer can be reversed meaning that with an increase of the PT100 resistance the user can select between decreasing current or increasing current in the loop. This could influence hysteresis behaviour. 

On the remark question of OP. The transducer only changes resistance value into different loop currents. 

Remark.

After contact with Weidmüller for more information they confirmed the above but were not able to explain the motivation at this time.