Minion poison stacks and 'Cycle of Putrescene'

The ring says:
‘+(18 to 27) Poison Damage for your Minions’ Damage Over Time Spells’

If I understand correctly Poison Wraiths cast a ranged poison spell that has a 100% chance to poison. So the ring just gives increased damage but does nothing for the actual poison stacks they apply right?

But when I than check my minion ailment tab (on epoch tools) it says ‘Ring (Unique mod): +22 Minion Poison Damage Over Time’. My poison damage from minions is also way higher with it equiped (22 is the average).

It really confuses me because it could also mean poison now does 28 base + 22 extra damage over 3 seconds.

Anyone that can tell me what it does?