Hello,
SAM's parametric simulations allow you to assign more than one value to one or more input variables to calculate values of output variables. That is useful for optimizing values of input variables, investigating sensitivity of an output variable to inputs, or other analyses involving understanding how output variables vary for a range of input variable values.
The stochastic simulation has more sophisticated statistical tools that allow you to define ranges of input variable values as statistical distributions, and to define correlations between input variables.
Best regards,
Paul.