Toad's Hammer and potential tiers?

In regards to Toad's Hammer from this: http://orangemushroom.net/2015/07/08/kms...oot-world/

Level 31-70 equipment get 2% on rare potential, while level 71-200 equipment get 3% on rare potential.
If Toad's Hammer is used on level 70 equipment with, for example, 2% DEX, to transfer to level 80 equipment, what will the outcome be?

Level 80 equipment with 2% DEX, or level 80 equipment with 3% DEX?

The tier will get updated so you'll have 3% DEX

Thank you for your help.