I just want to be perfectly clear on this point:
I buy a refinement.  I can either get 2 specializations, 2 focus items, or 4 enchanted item slots.  If I spend a specialization on crafting frequency, it now ups frequency for all my enchanted items by 2.  If I get a focus item crafting frequency, it ups frequency for all my enchanted items by 2 (and I'm assuming I don't need the focus item on me at the time for this to work, although I could be wrong).  If I add an enchanted item slot to an existing item, I can up the frequency by 1.  So all are equivalent bonuses, correct (except that with multiple items a focus or specialization would be "worth more" than a single item slot)?