You can pause manually for the color change. There is a bit of flexibility if you are late on the ideal time to swap colors. The ivory color dial has 12 layers. It should still look good if you intercept anywhere below the 10th layer. The numbers have 4 layers and should get a color change within the first 2 layers, so it has 2 complete layers with color.
The design was completely optimized to be easier to build. They are not interchangeable.