Hi LJGMDAD,
I also think the terminology is a little unclear but the first part of post #62 here should help to clarify it (although I would talk to them to make sure that you are clear on all the details).
In effect you can exchange two half layers or one full layer for free (except you pay for return shipping changes) and then if you need an additional exchange of either a half or full layer there is a reduced cost (35% off the current price) and once again they would pay for shipping and you would pay the return shipping changes for your half or full layer.
Phoenix