Thanks for your answer.
The point is that, when considering an alloy A(x)B(1-x), I user-set (some) bowing parameters (C) and the concentration x, and then the software interpolates the electronic/thermal properties (P, eventually present in the database) of the two species composing the alloy by using: P[A(x)B(1-x)]=x*P(A)+(1-x)*P(B)+x*(1-x)*C, as detailed in the reference I gave in the original post.
Now, to retrieve the interpolated properties I'm currently manually getting the properties of interest (P(A), P(B)) from the database and perform the interpolation myself. I was wondering if there is an easier way to get those interpolated properties somewhere, since they are already automatically calculated by Lumerical, but as you were mentioning they don't appear in the simulation results.
Hope it's clearer, thanks again.