The difference being is that the opening credits are always in motion in Z space, coming towards the camera. The end credits are static in Z space and only scroll from the bottom to the top of the screen.
This creates an issue with the blue echoes. The opening credits leave a trail behind them based on their path towards the camera. If the text stops on this path the trail of echoes will catch up to the text and you are just left with the white text. As in this example:
If I keyframe between the position of the first shot an the second the echoes effect doesn't work properly.
If I precompose the composition to a new one and stretch the frame that looks right over a period of time, I cannot change the angle as it moves up the screen.
If I keep the text moving in Z space, and set up a camera with a path that keeps the text in frame at the same position. So the shot looks static, but the object in frame is actually in motion, the echoes effect no longer works.
If anyone has any ideas I'd love to hear them as I am really stumped. I also hope I have been clear in describing my intentions and methods, let me know if any details are unclear.