I don't know exactly how long they have called for oil in trim pumps but it has been a while. The older Kiekafer pumps with the smaller, metal reservoirs used ATF, but all of the bravo pumps with the plastic reservoirs called for oil, as far as I know.
Eddie

I was just going through the bilge, and noticed that the (Volvo) drive trim pumps seem to be full of ATF, unless someone makes a red P/S fluid. The Kiekhaefer trim tab pumps seem to have a very light-colored (motor?) oil. This gets more confusing every day.

....I guess I'm going to have to start reading the owners manuals now. Dang!

There is not a whole lot of difference between ATF and Power Steering fluid. Actually most vehicles nowadays call for ATF in the power steering units. The ATF will work just fine in those trim tab reserviors. Our Bravo one calls for ATF, I've never seen a pump call for motor oil.