Autos don't need the light change, you should be able to continuously run at 18/6. With seedsman autos, however, I have seen journals where their autos were actually photos. Seedsman Seeds is most likely trying to minimize the ruderalis genes while keeping the auto trait, resulting in some actually being photos. If that's something you can live with, I would say go for it. Minimizing the ruderalis will give you better potency.