Difference between Phreatic and free and movable 1st layer results

I have tested running my problem with the 1st layer as phreaticand as free and movable. I got significant differences in the results. Which result should be more trustable?

If you set the first layer to fixed, it will be simulated as confined. Free & movable will assume an unconfined layer, moving the mesh vertically to adapt the top of teh model to the water table.

Sorry, I meant Phreatic rather than fixed.