Hi Elang, since getting a precise minimal bounding box can be a time consuming calculation there are various types of approximations.

The one in the object info panel is based off of the display mesh. If you click on it to open the "Edit size" menu it will do a more accurate solver based calculation in the menu.

The one used by ObjectList.getBoundingBox() is quick to calculate and uses the bounds of surface control points. It can be larger than the accurate bounding box.

Do this if you want a "tight" bounding box:

function excercise_06()
{
	var rnd = moi.geometryDatabase.getSelectedObjects();
	var bbox = rnd.getHighAccuracyBoundingBox();

	moi.ui.alert(
		'X Length : ' + moi.ui.formatCoordinate(bbox.xLength) +
		' Y Length : ' + moi.ui.formatCoordinate(bbox.yLength) +
		' Z Length : ' + moi.ui.formatCoordinate(bbox.zLength)
		);
}

excercise_06();

Understood... Thank you very much, Michael!