All that it guaranties is that all points on that wave have a definite relative amplitude. So, that is the beauty of the mode shape the mode shape does not dictate the absolute value of the deflection. Similarly you can do it for all of them and you can normalize these Eigen vectors, you have studied them. Commonly what we do is we take one of them, the top one you make it to unity and scale the others. But there are other ways of scaling and once you normalized it you call it an orthonormal Eigen vector.-All that it guaranties is that all points on that wave have a definite relative amplitude. So, that is the beauty of the mode shape　the mode shape does not dictate the absolute value of the deflection. Similarly you can do it for all of them　and you can normalize these Eigen vectors, you have studied them. Commonly what we do is we take one of them, the top one you make it to unity and scale the others. But there are other ways of scaling and once you normalized it you call it an orthonormal Eigen vector.