I've heard of some people taking clones in late flower but I've always taken cuttings during the vegitative stage because that gives the clone some time to take root and get some height on them, where starting new clones off while they're in a flowering stage can cause extra stress and even skock from going back into the re-veg state. Plus, when you take cuttings in their thriving, vegging state, you get more healthy cutting sites to choose from. Hope this helps a little. And its just my take on it, so far
Peace