Great questions A-Roe, and yes I do pull some fan leaves during flowering. Obviously, as everyone who has tried to look for it has found out, there is very limited scientific studying of how to perfectly grow a cannabis crop (for female plants at least). This is unfortunate, because it means that most of what does get published on how to grow cannabis is really just loosely tied principals that were actually studied on greenhouse crops like tomatoes. For this reason, I tend to make a lot of my cannabis garden decisions based on the cultural practices that I follow for growing different greenhouse flower and fruit crops, with an educated guess as to how it would apply to cannabis. I wanted to start by saying all that, just so that you don't think what I say next is set in stone as the perfect practice for indoor growers.
On a greenhouse tomato crop, there is a hard and fast number of 17 leaves per plant that you are always trying to maintain once the crop is producing fruit. From the first leaf to the last leaf ends up being about 6-7 feet, sometimes more depending on internode length, and the 17th leaf is starting to get shaded by the next crop row and is also past its peak efficiency for photosynthesis. This number has been researched to provide enough leaf surface area to photosynthesize the needed sugar for the plant to grow healthy fruit and maintain its current leaves and fruit.
We are not that lucky to have an exact number of leaves dictated for each plant to have ideal production without excess that gets wasted. But what I try to do is remove any leaves that are starting to get completely shaded from light, and remove leaves generally 6 weeks after they have been produced for maximum efficiency before they start to be too old to produce beneficial amounts of sugar. You should notice that the base of your final product colas are usually grown in around week 1-2 of flowering, so as you are reaching maturity at week 8-10 (6 weeks later) you will have just pulled the last few leaves below that point.
I hope this very inexact answer helps you understand why there is a big debate among cannabis growers as to whether it is beneficial or not.