I used cfl and a t5 for 3-4weks on 12:1 than a week of 12:1 with the 400mh then went straight to 8/16.
Mine seemed to stretch most during the week of mh 12:1.
If I had have left them another week they wouldn't fit in my cabinet.
I found that transplanting them and switching the light the next day gave them a good kick start. And they seem happy in the 2 gal pots now.
This time around tho I think it's easier to see that they will finish early.
@skunkwreck weren't yours like 15 days ahead when I flipped?