In that case I'm really not sure what the problem is. It sounds like you have your hardware setup correctly, but don't rule anything out too quickly. I have spend hours debugging my software just to discover that I had a bug in my hardware that "couldn't possibly happen", so I ruled it out hours before. (I have also had the same problem vice-versa. It's just part of microcontroller development, I think.) It doesn't sound like a power issue. The 11mV difference on your rail shouldn't be a problem; current draw is really what you should be looking at anyway.