Try out a +1 Death item while you're at it. Level 19 undead do show a nice difference over level 18 undead.
Here's an one such item from Maguuma_Stade:
http://www.guildwiki.org/wiki/Ingrid_Larson
Grim Cesta
Energy +10 (Req 8 Death Magic)
Death Magic +1 (20% chance while using skills)
Health +30
and pair it with:
Truncheon (there are a few versions of this in diff places)
Cold damage: 11-22 (req 9 Death Magic)
Halves skill recharge of Death Magic spells (Chance: 20%)
--- versus ---
Bone Staff
Energy +10
Cold damage: 11-22 (req 9 Death Magic)
Halves casting time of Death Magic spells (Chance: 20%)
Halves skill recharge using Death Magic spells (Chance: 20%)
+ Staff head (+5 Energy or +30hp)
+ Staff wrapping (+1 Death/20% chance)
---
So, you can spend gold on the appropriate staff head and wrapping to get the 20% chance of a halved casting time, and have the option to have more energy instead of the +30 hp.
or
Collect drops and have everything but the fast casting for no gold.
Then again, you could really splurge and use this in your off hand:
http://www.guildwiki.org/wiki/Bortak%27s_Bone_Cesta
Bortak's Bone Cesta
Energy +12 (req. 9 Death Magic)
Death Magic +1 (20% chance while using skills)
Halves casting time of Death Magic spells (Chance: 20%)
...and only be missing the 30hp.
Good stuff. 