It's actually not the same cost (Sponsored magic: Places of power is -3 refresh), but it doesn't seem like an issue to me. I'd still allow it.
It really is the same cost. Rituals is -2, Refinement is -1, together that is -3.
For -3 with 4 item slots (that can go into enchanted items) you have 3 options
Rituals (crafting), Refinement - No restriction on the items, but no casting
Rituals (theme), Refinement - Thematic restriction on the items, but thematic thaumaturgy
Sponsored Magic: Place of power - Thematic restriction on the items, but thematic thaumaturgy and evocation while at the place of power.
All seem like viable tradeoffs.