How invariant is the measured equation of invariance?

We prove that the measured equation of invariance (MEI) is not invariant to the excitation. The proof is based on the fact that different sets of sinusoidal metrons produce different boundary equations, even when the nodal separation is infinitely small. These results follow from the rigorous analytical derivations which are also verified numerically. The noninvariance of the MEI emphasizes the importance of the proper choice of metrons and indicates that this choice should be influenced by the excitation and geometry in question.