I see no reason not to, other than efficiency...you could do 21/3 or whatever, but if your going for maximum growth in the shortest time, why would you? If the plant can take 24/0 light for weeks at a time with no apparent ill effects and growth is proportionate to the additional light/time AND you're using little additional electricity...why not use it? You could maybe get them to veg with only 14 or 15 hours too, but why would you? Just conversing here...comments?