1. Open Altis with Eden editor.
2. Place object (Land_BarGate_F is a very good example).
3. Open the object's attributes and input a new set of numbers for position.
4. Compare the numbers you typed in to those that show up when you use getPos Object ingame.
5. Use setPos on the object, and supply it with the exact same numbers that you typed into the object's attributes in Eden back at step 3. Observe how different the position is visually before and after setPos.
6. Check object position again with getPos Object and you will see that these now seem to match with the ones from step 3, yet there is a difference between where it is shown in Eden vs. ingame.

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:

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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];

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You'll see clearly that it moves from partially on the grass in the editor, to moving onto the actual driveway ingame.