I have two flower rooms, one on while the other is off. In Room A I have some sativias that will need a couple extra weeks. Can I move the plants into Room B, when ready, and not have any problems with the extra time difference?? Sounds crazy, I know....
Changing light cycles requires extra light or extra dark. Always go with extra dark. I screw up my lights 2-3 times on every grow. As long as screwups are few and well spaced, you're OK. Its bouncing around with regularity that Herms you out.