Last summer, I changed oil in the tranny of my vintage Mercury that takes type "F" transmission oil. The tranny takes about 12 quarts. I had 6 quarts of SuperTech type F and 6 quarts of Pennzoil type F. I emptied the six quart of SuperTech in the tranny and started to pour in the Pennzoil. The SuperTech bottles were dark, but the Pennzoil bottles were yellow and you could easily see through the bottom of the containers. The Pennzoil had been sitting on a shelf for about a year and I noticed a residue on the bottom of the quart containers. After that, I would pour about half of it out, shake up the remaining oil in the containers to break up the residue of deposits that was sitting on the bottom and then pour it out. I went back to the SuperTech containers, inspected them, and noticed they had residue on the bottom also. I then put some Pennzoil in the SuperTech bottles, shook them up and then poured that oil in the tranny.
Since then, I've shaken up all my containers of oil before pouring them into the engine or transmission.