I think there is one factor that people in these threads tend to overlook. That is do we know that the original cable wasn't faulty or inadequate?

There are many, many cheap low quality cables out there for both power and interconnects.

I wonder how many companies doing demos will take a cable that for whatever reason doesn't perform the best as the control then swap it for an "upgrade" that sounds better when in reality it may just be an adequate cable for the purpose.

I am not sure how prevalent this is with power cables, but there are lots of examples of poorly grounded and shielded HDMI & USB cables that simply don't meet the specifications but at first glance seem like fine cables.

I personally wouldn't put it past a salesman to pull crap like that, especially considering the overhead on things like cables compared to a receiver.