Seems everyone forgot about the oil left in hydraulic lifters, they hold quite a bit, and the more valves (and lifters) you have, the more oil that gets left behind. I used to try and get the most oil out that I could by re-installing the old oil-drained filter, and cranking the engine with no oil in the pan. The cam compressing the lifters forces oil back into the filter on the "clean" side, a fairly large amount, too.
But I digress...... Yes I have heard that RedLine's chemistry cleans deposits that may have accumulated wear metals, spiking the readings in UOAs. Best to run an initial load of RL a very short interval, IMHO.