In the lower left window that has column headings "Entity" and "Status", click on the SG of interest, one-level below the "ObsUnitSet" folder. Its icon is a light blue stack of square clocks. (It is one level above where the icon is a single yellow square clock.)
In the window in the right, at the top, the "Status entity ID" is the OUS ID.
(This is different from the "Sched Block id" and the "Status entity id" that you would see if you clicked on the level below, with the yellow icon.)