We report on a simple technique that supports some recent developments on AES by Grassi and Rechberger and Bao, Guo and List. We construct a weight transition probability matrix related to AES that characterises fixed configurations of active bytes in differences of ciphertexts when plaintext differences are fixed to some (possibly other) configuration of active bytes. The construction is very simple and one might even consider it to be a little naive. However, the derived probabilities match recent results on 5- and 6-rounds AES derived through more sophisticated means, indicating that it might be worth a further investigation.