IT WORKS ! I bought a dozen eggs (still in Mexico) , put a rubber band around the carton, and set them upside down for 48 hours. Just now, after hard boiling the eggs and peeling them, I sliced them in halves. The egg white side and ends were perfectly even. No super thin ends.
I am so glad to hear this works! I don't think I have ever had this problem, but I don't make deviled eggs very often so having a thin white on the egg would not really be something I would notice. It's in my mouth and gone before I can notice it.