This is my leading assumption - that it's a two-slot item constructed at Great Lore with extra frequency.
As a one-slot item, either it just works once a session, or gives Fair / Armor:1 three times a session.
Reducing item strength for extra uses is 1:1. Using a whole slot for extra uses is 2:1, to create an incentive for doing so.
Are we talking Focus Item Slot or Enchanted Item Slots?
For an Refinement I could get two Specialisations +1 Item Power and +1 Frequency or I could get 2 Focus Item Slots or 4 Enchanted Item Slots?
I will asume we are talking Focus Item Slots (otherwise it gets into crazy town).
I use one Focus Item Slot for Power, the other Item Slot for Frequency for two extra uses.
Is that intentional? Its better to use the Refinement ability for extra Item Slots, than for Specialisations.
If we are talking about multiple Refinement abilities used for crafting it gets worse, because you cant stack the Specialistion boni that fast (you need a +1 for every +2).
Reread first post
You can also add additional item slots to frequency, to give you an additional two uses per session. The original extra slot benefits of +1 strength and new item still apply.
So we are talking Item Slots…
So for on Refinement ability you can get +1 to Power and +6 to freqency.
Is that your intention?