How much Damage is Cause Mortal Wounds?

[Nivra]

In monster_spell.txt from gitHub (angband/lib/gamedata), it says the following:

 name:CAUSE_4
hit:100
effect:DAMAGE
dice:15d15
effect:TIMED_INC:CUT
dice:10d10
lore:cause mortal wounds
message-vis:{name} points at you and screams the word 'DIE!'
message-invis:Something screams the word 'DIE!'
message-save:Your body spasms briefly.

I'm guessing this means that:
(a) You take 15d15 damage.
(b) You receive a cut lasting 10d10 turns.

Firstly, how much damage does the cut do?

Secondly, I think there's a description bug of sorts:

When examing a monster, the spell is shown like this:

... He may cast spells intelligently which cause mortal wounds (325), ...

I am guessing the 325 comes from adding up max(15d15)+max(10d10). But that's not really how much damage the spell does, and it's confusing.

My level 30 ranger has been avoiding all creatures with "cause mortal wounds" in its monster memory, but @ dlvl 40 they're everywhere, and he won't be anywhere near 325 hp for awhile yet.

[Timo Pietilä]

(cause wounds causing 325 damage)

My level 30 ranger has been avoiding all creatures with "cause mortal wounds" in its monster memory, but @ dlvl 40 they're everywhere, and he won't be anywhere near 325 hp for awhile yet.

I think that's bug in description, max damage is 225 and it is heavily biased toward average (15 rolls of 15 sided dice) so on average you get about 120 points of damage if you fail saving throw.