It definitely seems to show up more each moult. I have a blue DF spangle who was pure white after his first moult, but gradually has had more blue show through on his stomach and rump. Somehow it never shows up in photos though. I also have a grey DF spangle hen whose body colour is still definitely visible, but very diffused. She's around 8/9 months old now and it hasn't changed since she had her first moult. You can see it pretty well in this photo how the colour changes where, in a normal bird, the colour would change from grey to white. Her grey is almost pinkish.