Stacking offense question

In reference to first order executioner specifically, but other characters too, how is stacking stats handled? Does the 20% and 10% apply to the new max health total after you gain the health each time, or does it only apply to the original max health?

Example:

Say Executioner gains both buffs ten times. Will he gain 30% of 29,000 health, ten times? Or will he gain 30% of 29,000 health, then 30% of 37,700 health, and so on?