Auto Flower and switching the lights

I have a 4 x 4 Tent with a 600W QB288 V2 R spec LED light and growing 6 plants in 3 gallon pots. My issue is I have a auto flower in there with them right now and I am wondering if I should move her under a smaller light in order to keep the 18 hours of light. Which one would produce the best end?

Maybe have her under the big light when you can and move her under the smaller light before lights out.