The current reference for a model's datum target around a hole is typically the hole axis. When creating a datum target with an area, the area is placed at the depth of the axis when clicking on it to create the reference. There is no real reference to select the placement surface of the datum target area. Sometimes the area is above the surface, sometimes below. PTC Support agrees that this is the current functionality! Please enable a specific reference to allow for placement of the area to be on a specific surface. We can't do datum targets in drawings either because datum target areas don't scale with views (this is another IDEA). So we are stuck with issues both in the drawing module and the part/assembly module.