Appropriate use of S_s in unsaturated flow?

I've been reading the Van Genuchten parameters, and it seems like S_s is set to (usually) the porosity of the medium.

e.g. Sand, S_s  = 0.43, S_r = 0.045

The online FEFLOW help has default parameters of S_s = 1 and S_r = 0.0025

(http://www.feflow.info/html/help71/feflow/mainpage.htm#t=09_Parameters%2FMaterial_Properties%2Fflow_parameters.html)

Does the FEFLOW value account for porosity, or how does it actually work...?

It is important to note that FEFLOW references Ss and Sr as saturation, not as water content. Thus completely filled pores correspond to a value of 1 rather than the porosity. This is why Ss is 1 by default. FEFLOW accounts for porosity internally.