Hello Eric,
Yes, the reason is that my idea is to keep the script as close as possible from the reality with only one plate condition (FFFF) and then adding on top of it the "real conditions" by some fixed (SSSS or CCCC) or (not tested) edge points with stiffness and damping or by testing any other fixations that can be described in words of stiffness/damping/mass. It is maybe utopian but it is supposed to mimic what we do : from a plate of given dimensions we use it like that or we add some surrounding or glue it to have it clamped.
I have the feeling this approach is more general than to add different boundary conditions that are more "mathematical tricks" than real conditions.
We saw with the tests in comparison with FEM results it seems to make sense, or that this approach passed at least those few test cases.
From implementation point of view, I mean from the code complexity, it is in addition easier in comparison to add a new specific condition.
Christian