Shaper of Flames 25% more ignite damage

how exactly does the damage bonus work on Shaper of Flames (Elementalist ignite notable)?

Does it check for the highest Damage Type before increases/reductions/more/less and does it take in consideration damage taken (resistances, etc.) of the target? This is mainly relevant for archmage builds.

Take this example:

My fireball has ~2000 base fire damage and ~1200 added lightning damage from archmage/arcane cloak/etc. Fireball has 240% damage effectiveness so the 1200 gets increased to 2880, so now the base damage is 2000 fire, 2880 lightning.

After increases/more multipliers the fireball does 36k fire and 28k lightning. Ignoring resistances for now does it still get the 25% more damage even though the base damage is mostly lightning?

From my understanding it's all about how much damage the monster actually receives. Interesting you're going flame while I'm going ice.

Shaper of Flames says "for which the highest damage type is fire".

I am 99% sure that that can only mean damage received on the target (meaning after resistances etc.)

Ignites, Poison etc. use base damage. If that would have been meant here, it would also be called base damage.

There is a 1% risk that they strictly mean highest damage dealt (not received), which would consider increased/more damage mods but not increased damage taken, enemy resists and stuff. But that's really unlikely because
a) it doesn't say so
b) afaik no other mechanic uses damage dealt, why should this?
c) You can look at the wording of other mechanics and what that means there (which will be the same here). #% damage Leeched as Life refers to damage taken, so I assume the wording hear means the same (highest damage type = highest type of damage taken).