When you have certain genetic areas that are far above others you dont have to hit them every week. Like my front delts/traps i can take weeks off and they are still ahead of the rest of my body. Just tone down the volume some for your back workouts
post up pictures... its very suspicious that you are noticing growth.. usually its hard to notice stuff like that since we see ourselves several times a day in the mirror. usually its someone you haven't seen in a couple months who will see you and be like "shit bro you looking jacked!"