Sounds like fun, but you are losing me.
Was it not you who recently raised the question of audibility? So, if you want to make reductions in noise that are audible, they have to be put through a system, amp and speakers, a room and finally your ears. If audibility of noise is a concern, why are you measuring the AC at the wall? Should you not be measuring at least at the DAC's output to the amp and speakers, since there is a high likelihood that the system may filter any noise in the AC, rendering it inaudible? Why mess with the AC if it does not create an audible difference or at least a measurable difference as it leaves the DAC or amp? No, you may say, but you are measuring arse backwards if noise is truly a concern. And, you have mentioned no measurements at the business end, closer to the ears, to really know one way or the other.
But, have fun measuring the AC, useless as that may be. You seem to have some rituals aimed at something or other with no idea what you are actually doing, cool though it might sound.