I also got mine at BB. I have the Silver Premier status, so that allows a window of 45 days for return/exchange, as opposed to the 14 days. I read that on their website today before I called Apple to at least start a case for both of mine. Apple will "fix" up to 1 year (2 with extended AppleCare if you got that). I at least wanted it documented on Apple's end of the defects.
I do like your breakdown of the discoloring. Makes sense. But besides the fact I already bought 2 smart-covers that I really don't like that much, I don't want some rubber-baby-bumper fix-it offer. I want a unit that works as perfectly as an $800 Apple iPad SHOULD work, zero issues. Or just give me my hard earned money back, I guess. I'm holding onto the two faulties I have for now, wait it out a month or so, then see what's going on with all of this before I decide to return them to BB, or go thru Apple. (Keep in mind, Apple told me they would try to "fix" the one I send back....) Whatever that means, read into what you will. My thought is they would just send out a new one. BUT...I'm not ready to risk getting a new one that is worse. I'll just wait a while. Good luck.