Sketchplane-normal is the same in different door family instances, why?

hello Dynamiters,

I am trying to flip doors, but when I create the doors and later I obtain the reference plane and out of that, the Sketchplane and normal, somehow the normal (that you can see on the screenshot) and I would like to use for a logit to flip the doors, is unfortunatelly the same in all the doors, even though they are not at the same family instance. I have no clue how could I continue, any light on the difficult topic?

Thanks in advance

The screenshot

A part of the code

            for j, (p_v_list, i) in enumerate(door_dic.items()):
                    zVal = '%.2f' % round(p_v_list[0].Z , 2)
                    XYZ = rig.GeometryEncoder.ToXYZ(p_v_list[0])
                    door = doc.Create.NewFamilyInstance(XYZ, door_typ, inside_wall_dic[i], levels_dic[zVal], DB.Structure.StructuralType.NonStructural)
                    reftyp = DB.FamilyInstanceReferenceType.Right
                    reference = door.GetReferences(reftyp)
                    sketch = DB.SketchPlane.Create(doc, reference[0]) 
                    plane = sketch.GetPlane()
                    normal = plane.Normal
                    origin = plane.Origin
                    if round(normal.X,1) == round(-p_v_list[2].X,1):
                        door_list.append([origin, "hand_X_flippend"])
                        door_list.append([origin, "hand_not_flippend"])

Maybe you filter on the Defines Origin= True parameter for the Reference Planes

Just thinking aloud