ToME: the Tales of Maj'Eyal

Does the damage threshold on forge shield increase additively or multiplicatively? ie after its already blocking one type, would the threshold for the second be 17.25% or 30%

The threshold is 15% * (1 + currentTypes). So if you are currently blocking one type, the threadhold is 30% of your max life, and the third type threshold is 45%, etc.