8.25/6.6=1.25, so this means an increase of 25% to the stone's XP, i.e. 2.5million XP.
+1!
This works well with the revised curve in terms of maintaining the status-quo on statring effects of Ottos' (still be starting @ L22/L25 respectively without/with elixirs etc., as stone will give 2.5M/c.4M.), and also proportionately increases the stone's XP contribution to level cap.
So how aabut it, Devs - could you please increase epic XP stone effects by 25% and maintian the effectivenss of one of the Store's most expensive items on U29?
If so, I can guarantee you Epic Otto's orders, from me, at least!