Inaccurate?

Dampen Spell

( Player's Handbook II, p. 78)

[General]

From the lowliest prestidigitator to the most august hierophant, spellcasters both arcane and divine recognize the power of counterspelling. You are no exception. You have learned to channel energy into a foe's spell to weaken its effects. Although you fail to nullify the spell, you render it much easier to resist.

Prerequisite

Improved Counterspell (PH) ,

Benefit

You can use an immediate action to attempt to dampen an enemy's spell. As with counterspelling, you must identify the target spell as it is being cast. If you successfully identify it, you can expend any spell or spell slot to dampen your opponent's incantation. Because of your hasty, immediate casting, you do not fully counter the target spell. Instead, you subtract the level of the spell or spell slot you expend from the save DC of your opponent's spell.