Most positive hits from kills are only +1 (outside of certain mobs like Sir Lucan etc). Apprehensive is 400 points wide:
https://wiki.project1999.com/Faction
If you have logging enabled, open your logfile with notepad++ and do a find (ctrl f) for the "faction name has gotten better", and then click count. That'll at least give you an idea how many more you need to hit Indifferent.
-Mcoy