You might be on to something. I’ve only grown autos twice now. But this time I left them in the same tent as my sons regs. When we flipped to 12/12 Pipecarver and/or Oldcro pointed out they leave the plants on 18/6. So after however many days they got of 12/12 I put them in a separate section back on 18/6. Neither got large but the youngest one went straight to flower after a week or two of little growth.
I assumed that the back and forth of light duration mucked them up. The smaller plant should at least be as tall as the other but it stopped growing after 12/12. I think the stretch gave it the little extra size.
View attachment 135600
Here I thought they could grow together without issue with the regs or switching light duration but I guess I was wrong.