here is a quote from Al S. from the above link:
"These devices have significant low frequency winding resistance (57 ohms for the 193L and 63 ohms for the 193M), so they do not present a short-circuit to high frequency noise. They appear to work by damping high frequency resonances with the winding resistance, as the core behavior drops out above about 5 KHz."
Now Al is a pretty knowledgable dude, and the wording above does not inspire much confidence in how a choke used in parallel "appear(s) to work". Or if it really does anything at all.
I think what he was referring to at that time was that the choke will provide both a pathway for noise, and a load
for noise traveling hot to neutral. This is similar to what Quiet Lines and the like accomplish. You have to give the noise a load to dissipate into or it just moves from one place to another. Its been a long time since that post but I believe that was the essence of what he was getting at.
Plenty more reading over there if you are interested.
I find that they make a real difference at my house And that you can go a little too far with them too. (Having too many.)