What you are saying is also right and I think no one but Apple and the vendor that fabricated them know about it.
However, if I am not mistaken, TSMC is the supplier of these devices. Based on the experience that I have had with TSMC their yield is usually low! and we were not even working at 32nm! Their yield should be much lower at 32nm but if they can recycle it like the way they have done it, then it would be worthwhile!