I should also note there's not much point to the "Don't use abilities" tactic. They'll run out of mana before long and stop using abilities anyway, and before you have to face anything tough you'll almost always get an opportunity to save and restore HP/MP.

If you set tactics and then use O to exit the tactics menu rather than going down to the confirm box, it won't actually set them. I think if you go back into the tactics menu you'll find that it still has them set on "do what you like."