Mike Sullivan said:
That's not the average damage. There are ranged touch attacks involved here -- even if you hit on a 2+, your average damage is going to be 88.35.
If you hit on a 3+, your average damage is going to be 83.7. If you hit on a 6+, your average damage is going to be 69.75.
With the fact that it's one spell level higher than Disintigrate, that doesn't look too ridiculous to me.
I'm only comparing Ranged touch spells here.
The probability of hitting is the same for all the spells, but may vary alot depending on attack bonus for the caster and touch AC for the target. It would seem appropiate to compare the only the invariant factors i.e. damage when hit.