
Alfred, you force me to dig so deep into Emporea mechanics, to places where "no man has been before".

But I am grateful for that, just keep asking!

(I am a little smarter now as well)
So I checked it with the guys, it works like this:
1) regular damage of cannons is added to common damage calculations, it gets sort of "separated" from their ability
2) regular damage from all the sources is summed, improved by all possible bonuses imaginable (it happens at this point), then split to groups of opponents..
3) hailstones are applied.

if relation of upkeeps allows the full power of the ability, extra 150 damage goes to archers, 15 to the druid.
4) hailstone damage (that the unit group should get) is added to the regular damage (that the unit group should get)
5) amount of killed units is calculated
Now I deserve my coffee!
