I thought I would follow up this thread and say I have contacted my distributor and Stern requesting a warranty evaluation. Instead of pictures, I created a short video which demonstrates the problem:
http://vimeo.com/122073327
In the video, I think my measurement was too conservative and I should have said 1/8th at least. I did some searches and I cannot find a reference for anyone having a Stern game with a warped playfield.
I spoke with Chas at Stern and sent him the video link which he is going to forward to their QA team for warranty evaluation. I was upfront and asked for a populated playfield because this isn't just a cosmetic flaw, it considerably affects how the game plays (and levels). I also have a permanent disability and just can't do all the work needed for a playfield swap (anymore).
The game has a build date of August 2013, but I didn't get it until summer 2014. I knew there was a problem with the playfield, but never gave it any thought until recently when I was laid off from work and had time to tinker with my games more. I can't guess what will happen and will just have to wait for Stern or my distributor to get back to me.
Rob