Ah, I know what it may be -- since it runs from the spawn script, any creatures that have already spawned in your saved game won't be affected. That would be any creatures that were manually placed in the currently running module (the OC is comprised of multiple modules), or any creatures in areas that you've already visited if they're spawned via the On Client Enter script. I think most in the OC were placed manually, so you'd have to wait until you go to a new module (and forget about the NPCs in the current module), or start a new game, or manually change the settings of the NPCs directly.
Here's a little script to set it manually. Put this in your override folder, then while in game, click on an NPC you want to talk to so that they appear as your current target, open the console (`) and type
debugmode 1
rs talk2me
debugmode 0
Then try talking to that NPC with a companion.