To simplify this question, let's say the ocean is 3800 meters deep and 1 meter wide in either direction. Now let's add water equaling 1 cu meter on top. How much higher does the ocean get?
I suspect adding a meter on top is the equivalent of creating a new compressed layer on the bottom since the addition of the water makes the former surface compressed with the weight of the new water on top, the layer that was formerly 1 meter deep is now compressed with 2 meters of water on top, and so forth all the way to the bottom