Every screen I have seen on the 6s and the 6s plus is brighter on the bottom vs the top. I just compared to my new 6s plus to two other people who have 6s's here in my office. What would be the reason for that mechanically? Does the light source come from the bottom or is the light supposed to be evenly distributed? I am curious if other people see this. I notice it more in a dark room vs. a bright room. Could be my ocd too.