I built a house with a mildly odd shape, and it had a large roof on the second floor and four smaller roofs on the first floor. When designing it, the smaller roofs were edited and placed as one unit. That suited my needs just fine, but it might be nice to be able to edit and place such separate little roofs separately if you want to do strange things with them (different color for each, for example).
See the video at 6:10.