Block output differs for different instances with same parameters

I have developed a custom library block that is being used in several subsystems within a model. However, the different instances of the block generate different outputs while the block parameters are kept constant (i.e., the only variation occurs in the subsystem containing the block and not in the block itself). The trends in the outputs are the same, but the values are slightly different between block instances.

Is this a known aspect of Simulink models with respect to model complexity/model layout?

[Paul]

Generally speaking, if two instances of a block are identical in all respects (i.e., parameters, sample time, etc.) and are stimulated with the same inputs, then the outputs should be identical.