Attenuation question

If you look at the spec sheets for the Briess DME, you’ll see that for a fixed volume, the color goes up with gravity. For example, for their Pale Ale and Golden Light extracts, the colornin °L is 3, 4, 5, 6, and 7 for 1.020, 1.030, 1.040, 1.050, and 1.060 respectively.