number of Imbue Arrow uses is now 1 at level 2 and then +1 each 4 levels thereafter (ie. 2 uses at lvl 6, 3 uses at 10 etc.)

Imbue Arrow damage is now 1d6 per each AA level, minimum 10d6 (default nwn formula is (10 + half the level above 10)d6)

DC od Arrow of Death is now 10 + 1/2 levels of Arcane Archer + dexterity modifier, this DC is futher increased with feats Improved Arrow of Death I-X

Arrow of Death can be used once each 1 ingame hour (which is equal to 2 minutes)