Question on "Training Load Time Constant" numbers

I’ve used Xert for a few years now and feel like I’ve got a pretty good understanding of how it all works but I’ve never been certain on the “Training Load Time Constant” and the “Recovery Load Time Constant” in the profile.

There are three values for each for PP, HIE, and TP that can be changed but they never seem to change on their own. Are they tied to the number of stars or some other value? Is it one of those things that should be left to the background magic and never touched?

Thanks for the help.