I've noticed this too, especially on metallic paints such as IOM and CGM. I'm really considering CGM but this has me concerned and thinking about going with a non-metallic paint.
I understand that the color changes at different angles, but the change should be gradual as the angle (and plane) of the body changes. If the panels are on the same plane, then it just doesn't look right if there's a noticeable difference in color on each side of the seam.