There's a number of things that change those values within the game, but the fact is urm is still a mod, and often makes significant functional changes to games in order to allow everything it does.Nope the only mod i ever used was URM and i didn't even use it to change any variables in that save. I went from -3 to 0 somehow idk
In general developers hate when people mod games - because it makes it anywhere from difficult to impossible to track bugs - or know if the bug was caused by a mod, or by the game itself. We pretty much always try to fix any bugs we come across, but when there's no way to know the source, it becomes that much harder.
Of course you're free to play however you want, but just know that when a game is entirely unmodded, I can vouch for it being as close to a bug free experience as possible, and will do whatever is needed to fix any I come across - but once a game has been modded, neither myself, nor the vast majority of other devs will invest time into trying to figure it out.
But like I said - there's tons of things that happen in-game that will change Mia's values, most involve interactions with her, but some even involve interactions with Clara.