I really don't know all the answers. I believe there is a point of diminishing returns on lighting. For example, the most efficient grows I've seen use less wattage per square ft. This method just keeps the plants in a vegetative state with less light which results in a more efficient grow. At the equator, sativas never get more than 12 hours of light outdoors. It's not such a radical lighting schedule when I consider that fact. Here's an article on it: 12/1 Lighting for optimum growth and savings « Cannabis Dynamics