Here is an example where ASR may not adequately measure the component.
I at least would like to see an transient affect under load. The measurement was done all in frequency domain which only tests for steady state response.
I'd to see the two tests:
1. One if a frequency sweep and phase shift under load.
2. Two is a transient step response under load to see if there is excessive over or undershoot and rise/fall time retardation.
A lot of the cheap so called power surge protection it takes away the transient of the audio system. You can tell by listening the sound lacking vitality with the surge protector in the chain.