That's just it. How a thin 1/32" film of it, (if that), looks clinging on a dipstick means nothing. A dipstick photo can make any oil look good. You can't see the bottom of the catch pan with most oils that are drained at 2,000 miles, when it's just an inch or two deep.One thing about mine, when it looks dark brown on the stick, it’s jet black in the pan.
My HEMI takes 7 quarts. So I have a 2 quart graduated pouring pitcher I fill to accurately pour in the additional 2 quarts. I would guess the depth of the oil at the top of the 2 quart mark to be around 8 inches.
I can easily see the bottom of the pitcher clear as a bell when it's filled with the new oil. But the old oil coming out into the big drain pan isn't 2" deep. And there is no way you can see the bottom. Yet it looks almost like new on the dipstick before I drain it. And if anyone overchanges their oil, I do.