If you’re willing to AFK on a level 1 slot for 3 hours to unlock trading, you can test this!
Trade some perfect agility gems and level 1 armour to a level 1 file.
Equip them, and if you get banned for speedhacking (45 agility at level 1 is ~= 5600 agility at level 125), the formula works as you’re describing. Otherwise, it’s working as I describe.
Alternatively, maybe @Meta can clarify.