I have been following this thread, and have been learning a few things, but it still leaves me with a few questions.
Looking at the ping readings, I would think that Internet speeds would have a real bearing on your reading on the ping test. I know you are just looking for a different reading from plugin to unplugged. Just for the record this was my reading, but I have a very fast Internet.
Plugged in 16.2 - 13.3 ms
Unplugged 14.5 - 13.5 ms
I would think if your wifi card is working properly you would not see a much of a difference in the reading no matter what Internet connection you are on.