i had a similar experience with my new leds , turns out i could have them at 60cm high with no stretch, now when i do the math i see i could probably have the same environment but twice as many plants per light as the last grow. Bottom line is that it's less a matter of pure science in the home grow and more a matter of feeling, just keep adjusting until you find the balance that your grow needs. Think of it this way : anyway you need to adjust weekly and sometimes daily as the plant grows, so might as well start responding to that now. Hope this helps ! π