I've been to motor oil processing facilities(high end motor oil) and the manufacturers blend many ingredients into motor oil. They don't blend it for 20 minutes. Several hours. Addition of ZDDP to an oil change does not make it a component of the oil. Its just ZDDP flowing around with the oil, NOT PART OF THE OIL OR ITS LUBRICATING SYSTEM. As such, it does its own thing and will probably combine with anything at the bottom of the pan or be the first to be at the bottom of the pan.