Yes, there is at least 2 quarts of fluid that's untouched when you remove the tube. You can see from this screen capture where the top of the drain hole is on the pan. Everything in the pan would be left behind. You have 3 options: leave it in, drop the pan, or suck it out.I'm going to attach a portion of the change document. But yeah it refers to an "Adjustment" document which is a pain to follow. (Hopefully Toyota doesn't give me any trouble but it's not the whole thing)....
So pulling out the tube, aka "oil filler tube", leaves a lot of fluid?
I agree that your method is much simpler....
My approach is the same simple approach used by many transmission fluid exchanges. Put back in the same amount of fluid that you extract.
I'm surprised that no one else is performing a fluid exchange like I am. Maybe this will become the new standard?