Robust Design- same results for different models regarding N

[ayabnz]

I’m running Robust Design for rodents trapping data (7 primary occasions*4 nights each). I have 3 different sites which I want to compare (I refer to them as “groups”).
The problem is that no matter how I define N (N(session)/ N(group)/N(session*group), for each model I got the same deviance and AIC. In addition, defining “N (g)” leads to estimations (of N) which are the same as those that are received for the N’s of the first session when defining “N(group* session)”.
I guess I’m doing something very wrong – maybe you can help me and tell me what it is.

Thank you
Aya.