OK folks, what is the magnitude of the 7th harmonic on Arnies second graph? Do you think that it is -125dB ? Well, that's wrong, as you have to subtract 30 db from it, because the graph does NOT start from the top That gives -95dB for the seventh harmonic. My RS case 7th harmonic in my test is about -110 to -115db dB. My residual with a VDH cable is usually about 120 to -125dB.
Remember, the important thing to consider here is the 30 dB offset in Arnies measurements. Distortion products must be measured against the reference signal, in Arnies case, but my ST1700 does the normalization automatically, so I don't have to change my measurements to get the correct result.