compared to each other there will not be a lot of difference. Compared to deck 2, there IS a difference in the distance of the motion of the ocean.
For example balance a pencil on its eraser (so it doesn't slip as much) on a desk. Think of the where the eraser meets the desk as the waterline of the ship - in the center of the width of the ship. Now move the tip of the pencil to the right and left and see how much more distance (movement) happens at the tip vs down near the eraser.
Remember that the Dream / Fantasy are about only 140 feet wide, but they are about 1,100 feet long - so forward and aft are a lot farther from the center of the ship and that means even more movement in those locations. But don't worry about "violent" movement except under extreme circumstances (ie hurricane). The ship is a long slow moving teeter totter with technology to help minimize the rocking and rolling motions of the ship at sea.