Thanks for the technical paper...i'm evidently over-thinking this issue. I was messing around with different power amps and trying to understand some of the differences that I'm hearing. Nothing scientific. If this technical study is legit it makes one wonder why these figures are published at all.
Damping factor can be an indicator of the sophistication of a power amp design. The reason for that is difficult to explain without getting super technical (this is covered in senior level engineering classes), but it involves gain, negative feedback, and stability...in other words, the amplifier's ability to correct proportion of input signal vs output signal, because that's what an audio amp should basically do. You put signal in, and get signal out that is exactly "scaled up". Engineers have achieved astronomical DF specs in solid state, push-pull type amplifiers (class AB, G, H). There are many patents relating to this, but there is a point of not being able to tell the difference sonically, as has been said. It's bragging rights.
Damping factor is manipulated extensively in solid state and tube amplifiers intended for musical instrument use. There are also many patents relating to that.
Traditional PWM class D amplifiers have inherently low damping factors, and again this is difficult to explain, but it relates to the stage that actually generates the PWM limiting gain, which reduces the effect of negative feedback, which means that the amplifier's ability to correct errors in proportion is limited. It's common for this type of amp to have damping factors in the 20 to 50 range.
Higher damping factors are possible with modern class D amp technologies. This gets the amp into "it doesn't matter sonically" territory. That's where the Prolite 2.0 is at.