Less Hair
As mangled as the FDR and the CVR control unit look it is no wonder that the parts are all over the place. You can assume that the plane completely disintegrated on impact at the ocean surface and all mangled parts somehow sunk to the ocean bottom. Even if it is only 15m deep the parts can be several meters apart. Dive and underwater visibility conditions are poor as you can see in the video. So it might take some time until they find the CVR data module or whatever is left over.