Jeez, you're right
that's welcome news.
If it's fine by you, I'd summon lvl 4 instead in that case. If not, I'll do with 3 this time and conjure 4 next time.
Anyway, thanks ^^
I'm not quite sure whether additional powers are chosen by the GM or the player. If I'm to choose, I'll pick Bind (or Binding, I forgot). But I guess it won't matter anyway.
You already rolled for force 3 so we'll use that.
Since you just summoned a random water spirit I'd say it's powers are chosen by the GM at random.
Results of the summoning:
-water spirit will appear and owes you 2 services.
-spirits optional power is Weather Control.
-you need to resist 2 points of Stun Drain