Instinctive training is an option and does work to a greater degree for some, an incredibly small percentage and absolutely not recommended. I will always believe that it will never work as well as a pre-determined plan of attack with regular modifications. Based upon you saying that your schedule just absolutely doesn't allow this, I'm presuming that you would do it differently if it did.
Most of us here on this board have no right or reason to do what "body-builders" do, it's totally different for them. Your stats suggest a few things, you probably have a nice build, better than most even, the problem isn't how we compare to other people, but how close to maximizing our potential are we and what do we need to do to challange our bodies the most. You may be getting good gains from your program, but good is the greatest enemy of great. The next few ideas are basic, but should be applicable to you due to your age and lifting experience, muscles recover in 48 - 96 hours, depending on the size of the muscle group and the intensity of the training, if your muscles are recovered and you do not train them you are missing out on growth opportunities, the biceps and triceps are the smallest muscle groups and should be worked twice a week (once you are a competitive bodybuilder and your arms are the exact right size and proportion to the rest of your physique this might need to drop, until then...)
I absolutely never questioned your workout ethic, but have trained several people with years of lifting experience and showed them how to workout smart and produced even better results. I will always be a fan of changing your program up every two months, sometimes the changes may seem like a 180 degree change and sometimes 1 degree. Anyone who works out with a non-biased, knowledgable trainer will always produce better results than without (almost every top bodybuilder has a trainer), for every story you hear about someone that does something and works for them you have an exact opposite story that works for someone else, what matters is what works for you and if you have only tried it one way you don't know if another way is better. Sometimes leaving something you know and later coming back to it will produce even better results than staying with it.