Hmm, I beat Maat on PLD a couple of years ago using no meds, just a tavnazian taco and AF armor. He hit for almost nothing, and I had several hundred MP after the fight. I believe the most his Asuran Fists did was about 60 damage. I never had to use Invincible.
I was level 66 and I'm a Tarutaru. Sword was capped and Shield was capped for level 65.
You are doing something very wrong.