The feat Heighten Turning has the following as part of its benefit:
When you turn or rebuke undead, you may choose a number no higher than your cleric level. Add that number to your turning check, while subtracting it from your turning damage roll. (Libris Mortis 27)
So we're all on the same page, here's a summary of the special attack turn undead:
- When a cleric makes a turn undead attempt, the cleric first determines the maximum Hit Dice of the largest single undead that can be affected by making a turning check (1d20 + Charisma modifier), the result found on a chart that yields a Hit Dice outcome of between the cleric's level −4 and the cleric's level +4.
- Then the cleric determines how many total Hit Dice of undead are actually affected by making a turning damage roll (2d6 + cleric level + Charisma modifier). There is no upper limit to this result.
The feat Heighten Turning lets the cleric increase the turning check by +1 but decrease the turning damage roll by −1. The cleric can do this to a value up to the cleric's level. Reversing the polarity would've made the feat's use obvious in the face of a horde of low-powered undead creatures, but the way it's written instead makes the feat just weird: The cleric tries to turn a lone powerful undead creature while simultaneously limiting the size of the creature and his ability to affect it.
What are the optimal circumstances in which to use the feat Heighten Turning? That is, what numbers have to be present on both the cleric's side and the enemies' side for the feat Heighten Turning to be a good idea? Is the feat one that looked good on paper but is useless in actual play? Is there ever a certain point at which, or a certain build wherein, it's the ideal feat?