One important thing i learned, don't attempt this procedure when the air is cool, it makes the plastic less pliable. For what you charge for 4 plastic pieces and 4 screws, you should include a tube of superglue from the dollar store.
On the unit that sat inside for a little while, the plastic was at room temperature on the Packout unit. The second unit was in the garage, it was later in the evening, and the plastic on the Packout became less pliable. I actually cracked the plastic on two corners...