Oh no, Platonic, Antagonistic, and Romantic are all on separate tables for that reason. A Platonic relationship will eventually hit the negatives for Favor because once they’re to 0 Fate, you have to start subtracting from Favor. At that point either you use an Endeavor or two to salvage the relationship, or use a Transition to show the friendship going sour. Regression scenes are optional, which lets you decide which of those you’d prefer. Endeavors can help a lot because you can write them a letter and then visit, which can add quite a bit of Favor!
Omg the skies have parted and now I can seeeee!!! <3
This answers so many of my weird one-off questions around fate/favor. And also reinforces that I had waaaaay too many SCs, but I think I've sidegraded most of the unimportant ones off to NPC land by now. The rest I will weather the storms of fate and see who decides to hate me for being ignored ;)