RQS Apollo F1 Auto Indoor soil

The two journals I'm currently keeping show quite clearly how important good lights are. This plant here is a week younger, but has grown considerably more. Whilst the height is about the same, more leaves have developed here and they are also larger. The outsides of the leaves have been slightly curved upwards for a few days now. I've never had this with my plants before and I'm not sure what it means. Colour and growth look good.