SM.N is created by an initialization function call inside the mask. This function is p coded so there isn't anyting to see in how it is calculated. Essentiall, the function takes the parameters you entered into the mask, and generates the SM structure for use on the internal model. You can usually tell by looking at the help and simulink model what most of these values are, but some of them are calculated uisng proprietary algorithms that MathWorks cannot expose to the public because it does not own them.
Regards,
Joel