Sunday, October 7th 2018
"Ping Quality" is a term that is provided by PUBG as a parameter for the match as a whole. It does not represent the player's ping to the server. My interpretation of Ping Quality is that "High = Good, Low = Bad". Note that the variable is called PingQuality and not just Ping. I've added a tooltip to the Ping Quality display in match reports.
If I can get an official answer on Ping Quality from PUBG I will post an update.