[POE 2.] - Exposure % Increase stacking nodes/support gems.

Does anyone know how the increases of an exposure work? I see that two sources

of the same exposure don't stack and only the strongest one takes effect.

However, there is a support gem: Heightened Curse + Strip away that increase

the effect of Flammability for example. There are also nodes in the tree such

as: Cremation, Overexposure, and Exposed to the inferno that increase exposure

effect. Exposed to the inferno also makes it so fire exposure you inflict

lowers total fire resistance by an extra 5%. The wording seems ambiguous and I

personally don't feel very competent in deducing it myself unfortunately. The

Idea hit me by wondering if you could annoint all 3 nodes on a strugglescream

Amulet and have a very powerful exposure.

Flammability is a curse, a different kind of debuff from exposure. Heightened Curse increases effect of a curse it supports.

As all increased modifiers, increases of exposure effect stack additively. For example, you use a skill that applies a default fire exposure (-20% to fire resistance). With Strip Away support and Cremation, Overexposure, Exposed to the Inferno notables, the exposure would lower fire resistance by:
20 x (1 + 0.3 + 0.25 + 0.3) + 5 = 42 percent.

On a related note, something is wrong with power balance here. Support gems should be substantially stronger than common notables.