The only way you could fix this is if a modder were to do something about it, it's just an issue because the Pipboy was never intended to be in your hand so something about the new mesh causes your character's first person mesh to shift to the left. Not a lot you can do about it, unless you know how to fix it with a mod/fix the existing one. This problem occurs with any hand held Pipboy replacer so if you found a fix for one it should work for any of them.
by 
Calendar
