Turning Paradox

[tyckspoon]

But I apparently didn't catch your real problem earlier, and I have to question the rationale of your intent. 20HD zombies are supposed to be tough, that's why they have 20 hit dice. And their lich masters aren't as resilient, that's probably why they have zombie minions in the first place.

I find it incongruous to expect that a hulking 20HD zombie (CR 6) would be as susceptible to turning as a ghoul wizard 4 (CR 4 and +2 turn resistance). If you believe otherwise, perhaps the problem lies elsewhere in the system.

A level 6 cleric should be able to use his anti-undead class feature to achieve something useful against a CR 6 undead. Doing 6d6 damage against 20d12 HD is only marginally more useful than doing nothing at all with a normal turning check. Both are less useful than what the cleric could achieve by ignoring Turn Undead completely and casting a spell instead (or perhaps using a Divine feat to turn one of those borkened Turn uses into something useful.)