Also note, based on personal experience, that the increase of potential rune's attribute bonus is an addition of 4. This is true in the case of comparing the 1st tier level to the 2nd tier level.
Since Potential II gives a +6 to all attribute bonus, Potential III gives +10.
I did this with the intention of creating the product with tier 2 runes. In this case, among the materials required were already transmuted to their next tier.
Magic II, Resistance II, Vitality II, Power II, Mind II, Endurance II, Triumph III, Excite III, Guts III, Rage III, Magic Damage III
In common sense, the runes after endurance were the products of the ones that came before them. I found the bonus increase for the tier 2s on these runes to be a value of 3 specifically.
Finally, do note that Potential III is a 'bind' rune.