The 1/4" 3pt well only float from the point you let go of the valve. Try it without anything on the 3pt. and you can see. The kicker is you can not drop it at the same place as you can with position control.
I just hold my lever down when tilling, blading, and ect. I do have my drop valve set for a slow drop.
When I use my hiller I have check chains on it, and when the chains get tight I let go of the 3pt lever. Now it can float up but well not go any lower, at that point I could take the check chains off it would not go any lower. I guess the point is 1/4" 3pt sucks and I don't care for it eather, and it well float up from lowest point you let go of the lever.