05-08-2015, 08:43 AM
Hmmm... sounds very strange. Really all demands? I cannot recall ever seeing a problem with such symptoms.
No, I cannot really see how this could be a rounding error.
I am afraid it is very difficult to make any useful guesses as to what might be the cause, without seeing the model. Of course elastic demands may reduce demands below COM_PROJ, but probably they are not used in your runs.