I've been doing 5x5 for a few weeks now and have already made some gains, but I didn't realize until today that I had overlooked something. I never realized that on Fridays you are supposed to do an extra set for 8 reps using the weight from the third set. Do you think it matters if I do this extra set or not? Contemplating whether or not to start doing it, since I've already been making good gains without it. Thanks.