In GDL you need to do coordinate transformations (move the local origin in X, Y, Z direction then create things relative to the current location of the local origin). ADDX, ADDY ADDZ are such commands.
The DEL command deletes the last number of these coordinate transformation, which means it undoes those transformations.
There must be and error in the script because it is trying to delete more transformations than was performed. E.g. 3 coordinate transformations were performed but it wants to undo 4.
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