Questions about buoyancy

[fluidkocy]

When I float a rigid body in water, which is simulated as ice, there seems to be a discrepancy between the theoretical value and the simulated value.
In the first image attached, the density of the rigid body is 1000. The rigid body should not float above the water surface, but it does float a little.
In the second image attached, the density of the rigid body is 1100. Theoretically, the rigid body should sink, but it floats and appears above the water surface.

I would like to know what kind of calculations are used to obtain these results, what parameters are applied to the buoyancy, and if there is a good way to do a solid calculation on the buoyancy.