I understand how engines can detect knock and then reduce the timing, that makes perfect sense, like if you put low RON grade fuel in and it knocks, it can detect this and reduce the timing to compensate. What I struggle to understand though is how it increases the timing when you fill it with super unleaded 99 RON. I've read that it takes a couple of full tanks before the timing adjusts, but how does it know you're using higher grade fuel? Does it gradually try to increase the timing in minute amounts every now and then and see if it works without knocking? This kind of trial and error approach which would inevitably cause knock at some point just doesn't make sense in my head.