Not sure if this applies to all objects and to what extend, but some have minimal or practically no offseting (i.e. Land_CnCBarrier_F), whilst others have huge offsets (i.e. Land_BarGate_F). It seems to mostly apply on the X and Y axis, at least on the objects that I have tested.
If you want a quick way of checking this out, I suggest using the same test parameters as I did in the screenshots. Place the aforementioned Land_BarGate_F, placing it at the coordinates [14480.037, 16828.01, 0] (Altis Internation Airport parking lot) in Eden, use 134.82 for Z rotation, and putting the following in its Init field:
--- cut here ---
editorPos = getPos this;
plannedPos = [14470.71, 16832.11, 0];
this setPos plannedPos;
newPos = getPos this;
hint format["editorPos: %1\n\nplannedPos: %2\n\nnewPos: %3", editorPos, plannedPos, newPos];
--- cut here ---
You'll see clearly that it moves from partially on the grass in the editor, to moving onto the actual driveway ingame.