Were they stunted, or just squatty genetics?
The plants will tell you how they're handling the light. They're happy when the topmost fan leaves are flat and level. If you see taco-ing, canoe-ing, edge curl, twisting, etc., they want less. If they're praying an hour before lights out, they're ready for more. With powerful LEDs, I like to hang them high, and use the dimmer to respond to what the plant asks for.
I think due to my variables. Transplants from solo cups, too small pots (3 gal), one did slightly better that was in 5 gal than the others w/same variables. My seed source is bona-fide. I've learned that I won't grow in less than 5 gal pots and won't transplant next time. Was wondering about any other expertise w/high power l.e.d. lights. I'm going to try the photone app, as I don't have a light meter. One I grew outside in small pot had better stretch.
Things I've found to help create more stretch have been warmer temps, dim the lights, increase exposure to infrared. I found these out because I wanted short and squat plants so I do the opposite. Not a problem just a well researched home grower. Hope it helps!