There is no such classification.
Since your vague assertion is sloppy with its pronouns, let me ask, to be clear: are you saying that there is no difference between peng and peng jing as descriptors in Taijiquan? If that's what you're saying, I can quote from several books to show you that "peng" is used to indicate a directive jin while peng jing is used within Taiji to indicate the basic neijin itself. What is your assertion?
BTW.... don't forget that you have a number of questions in the thread that you haven't been able to answer yet.