Not quite. Without the Combat Alchemy skill, it's 162.5% (Elven Luck divided by something), and with it, it's 225%. That's a 62.5% increase from the base damage and approximately 40% from the damage without Combat Alchemy. For comparison, a third-tier attack with Cold Steel and Fire Attack from Chaos (the maximum you can get, if I haven't forgotten anything) gives only 35% of the base damage. And Luck 3 with artifacts and Elven Luck gives exactly the same 62.5%.