Can anybody explain the real-time changing station display in the UI?

On the “next stop” tile in the upper right corner in the Apple CarPlay display there is a circle that purports to show (I think) the real-time status of the charging station that you’re heading towards.

Does anybody know how to read the display? Is it really real-time? What do the colors of the segments mean?

On our last road trip EVgo (and EVgo eXtend) stations showed up as a circle with four segments, two blue and two grey. The circle never changed over the 90 or so minutes it took us to get to the station. So I don't think the colors are real-time utilization…