Hey there, thought you might want to know about this one. It's not so much an issue as an exploitation. You know your mod enough to know it allows the spawning of many mobs within modded and vanilla minecraft up to even the wither. However, with most, there is a balance of a kind, necessary tiers, a much higher power base needed, etc. This is not so with Ars Magica 2 bosses. So far as I can figure, and by no means am I in any way certain or even if this is by design, all the bosses I have tested seem to default to being Tier 1 in the factories, as if the mod does not recognize them as anything more than a zombie or some passive mob. Even the Fire Guardian, which is the penultimate boss to fight in the mod is Tier 1. With minimal power setup or work, one can create a factory that is stupid cheap and gain super high levels of overpowered-ness with this. Red point, green points, it does not matter. I thought to advise you of this, Maybe a readjustment in power and tiers to ensure nothing is being exploited, not sure. Maybe I am just being a spoil sport, but this seems to me a bit wrong. (shrug). Does not seem right to get a couple stacks of red points in a matter of a few hours, tis all

I had a look at the code and I can see why it is happening.
The AM2 Guardians all give 5 xp when killed and this is the default value that I use to map onto the different tiers. Because it is such a low xp for a boss, it gets mapped to the lowest tier.

The best way round this is the same that I do for some of the vanilla mobs and that is to change the tier that they are mapped to (eg. see S:globalTierIIIMobList). They will still drop the same XP on death, but they will be forced into a different tier.

eg.
S:globalTierIIIMobList <
Woot:none:Enderman
Woot:none:arsmagica2.WaterGuardian
Woot:none:arsmagica2.EarthGuardian

or up it so the TierIVMobList if you prefer.