Does this symbol in the pictures below represent height above ground level or altitude above sea level? There are huge differences between them and the Grid MORA values, so I think there may be heights from the ground, but I couldn't find the answer from the sources.
The Jeppesen Charts legend explains the symbol as follows:
17 — Some, but not all, terrain high points and man-made structures are depicted along with their elevations. Generally only high points 400’ or more above the airport elevation are shown.
18 — Arrow indicates the highest of the portrayed high points within the planview area only.
So these numbers correspond to the elevation above mean sea level (AMSL) of the terrain high point or man-made structure in feet.