OP, don't take this the wrong way but it seems like you're pretty stuck on certain per-concieved notions that you have based on experiences and educated guesses. I'm not here to tell you if you're right or wrong but this might shed a little bit more light and help you learn more so you can answer your own questions.
Its a brief video but it really is very interesting if you're actually interested about oil and how it makes a difference in your engine.