Do light leaks really matter during veg?

I am running a 18/6 in a tent with the zipper half open so it isnt so hot in there, and go they benefit the air conditioning in my room.... Next to the tent, i have an other clear propagation tent for my seedlings, and future clones, and it is running 24/0..... The Vegging plants are all doing ok, besides the Bag seeds, and i think it just has to do with genetics... Now i know the importance of getting good seeds... anywhoo.... The veg cycle turns off at around 8am, so i am most likely asleep, so i dont get to close the zipper in time.... I would, if i thought it was really a big deal... this is why i am making this thread...... Could my plants be doing any better, if they get 100% darkness during those 6 hours of off time?... Was just thinking how the moonlight gives off light, so its never 100% dark outside, and the some outdoor stuff grows MASSIVE!

Sure, I could go on google, and ask, but i really wanna hear from you pros that have been doing this for a while, and want input from more than just 1 source..

Thanks!