I have a theory for Outdoor: In the early stages the fan leaves are responsible for the general growth of the plant (roots and steams) also to inhibit the growth of lower branches and competition from another plants; the more fan leaves with direct sunlight the faster the plants grow. In flowering stage the sugar leaves are responsible for growing the flowers; inside buds/sugar leaves don't get enough direct sunlight even if you have lots of fan leaves in the outside and they get all fluffy.