An automatic transmission is different from a manual transmission. Automatics have clutches that have to have friction to engage. Thinking about preventing this potential failure by some amateur hour addition of lubricating additives is just foolish.

Stay with what the manufacturer recommends. The manufacturer has invested thousands and thousands of development manhours in this transmission. They are smarter than we are relative to this subject. Logic says you should follow their advice with one caveat. The sealed for life thing is most probably a marketing ploy. I choose to service my transmission, but that is not the same as choosing to pour in some snake oil.

Steve