If you look carefully what you will see is that the outer vertical element is probably the same height however the crossbar element has more than just an arch, it is actually sloped upwards. The inner vertical plate of the barge board connecting the other side of the crossbar goes higher than it did before. You can see this by comparing its height to the vertical turning vane elements right behind it.
Trying to get a larger mass of airflow moving outward to control front tyre wake.
Edit: you can also tell that it's talker when comparing the before and after picture if you look at where it is in relation to the connection for the front suspension wishbone is right in front of it.
