Boss Gitsmasha said:
No, the Unnatural characteristic thing isn't a typo. Unnatural characteristics (+) provide a flat bonus rather than multiplying the characteristic's bonus.
How it should have been handled right from the beginning, too. Multipliers tend to "explode" some way down the road, and it's not hard to see how that could break the game - especially in a system where Toughness works like a second layer of armor, rather than minimizing the effect of sustained injuries.
That being said, I have to say that it could simply be dropped altogether and replaced with a flat +X modifier as part of the normal characteristics bonuses. It seems so unnecessarily complicated to preserve it as a specific trait. Sure, one could say that UT still works differently for the purpose of opposed tests, but imho the differences are unwarranted. Either somebody is stronger, or he isn't.