"The side latch, does NOT unlock the top latch - both of them lock independently and have to be manipulated simultaneously."
Well, I don't consider the top latch to be locked on the earlier models. Let's consider the two terms - latched and locked. Before the perfected model, the top latch was not locked at all (in the sense of having to unlock it first before you could operate it) - you simply grasped it and lifted up (thus releasing the latching mechanism) - there was no locking mechanism to prevent the top latch from unlatching when you pulled up on it. On the perfected model, the side latch releases an internal lock on the top latch, so it can now be operated just like in the earlier models. After you push the side latch forward, you can then open the now unlocked top latch, as long as you keep holding the side latch in the forward position.