Sorry. I just meant to follow the link to the errata that had been posted.
Do I really need to? Look at the erratum for Vessel of the Clouds (emphasis mine):
delete the reference to +2 for metal in the discussion of ReTe (there is no modification for simple movement)
Not only is there no +2 metal, it says exactly why there is no +2 for metal and the explanation does not restrict itself to fast movement. And if you think this only applies to metal, look at the erratum for The Heart that Could Move Stone.
As for not explaining, I didn't think I needed to explain how an explicit comment about simple movement applies to simple movement. This looks just like a ridiculous dig at me, as you don't really need me to explain that, do you?