Thats a great question to ask Ed Rosenthal... Know him? If you dont, i suggest looking him up and reading everything he has to offer. He's pretty knowledgeable about this stuff.
Acording to him....... let me find that article, hold on a minute.
OK
West Coast Cannabis magazine Volume 2, issue 12. December 2009
Ask Ed:
Question:
Should fan leaves be picked during the flowering stage so that lights penetrate lower areas or do fan leaves bring in energy to the flower?
Eds response:
Buds grow and mature when exposed to bright light. Buds that are shaded remain small. For this reason it pays to remove fan leaves thats are blocking light. Fan leaves that are not in the way contribute sugars to the plant so they help growth.
Aside from the top canopy, which consists of larger buds in direct contact with the light source, ........................
article goes on to the second level of canopy and does not apply to original poster of this threads question so i'm saving the carpel tunnel and not typing the whole thing.
But this should help a bit, just cut the ones that are blocking light on lower buds is what i'm taking from his response.