Network Neutrality is protected by law in many countries over the world, but monitoring has to be performed to ensure operators conform to the rules. The Wehe application, jointly developed by Northeastern University and the French regulator ARCEP, allows users to take measurements and analyze them to detect possible traffic differentiation. This paper presents a test bed designed to evaluate the detection capacities of Wehe; by computing the detection probabilities and estimating the potential benefit of an operator willing to differentiate while avoiding detection, we fine-tune and compare the main differentiation types (throughput, packet loss and delay) that an operator could implement.