Sadly, I would have to agree with you. That solution lasted for about 5 days and started acting up again, so I just gave up the frustration, hoping an update would eventually resolve the issue, and started just keeping my iPad plugged in all night.
Well, I have no idea why, but everything magically started working correctly again about 10 days ago, which coincidentally coincided with the date of the latest Kindle app update. This tells me our issue really has nothing to do with the settings on our iPads but with the app itself, whether that was the solely the Kindle app or a conflict between the Kindle app and another app. It’s a shame we can’t get the people who are supposedly knowledgeable to realize that so many of the users of their app having the exact same problem really should warrant a serious look into the problem and not excuses.