How does the orcale's Inevitable Critital Hits works?

Assuming I start with 300% crit damage bonus, I failed for the first crit check, so crit bonus drop to 300%*(100%-30%)=210% (30%less), now what if I again failed the second check? Is it 300%*(100%-30%)*(100%-30%)=147% or 300%*(100%-2*30%)=120%? Does the 30%less crit bonus stack multiplicatively or additively?

"Inevitable Critical Hits
Hits which could potentially be a Critical Hit but do not roll a Critical Hit will re-roll Critical Hit chance until they succeed.

Hits have 30% less Critical Damage Bonus for each time Critical Hit chance was re-rolled."

from the skill descriptions

From the wording, the "30% less crit damage bonus" has to be additive with itself. So after 4 missed crits you get to 120% less crit damage bonus and it stops calculating there. After that you do your normal non-crit damage on crits since it can't go below.

Any other way of multiplying the less crit damage bonus would also destroy the servers with calculations.

"

Hits have 30% less Critical Damage Bonus for each time Critical Hit chance was re-rolled."

This does not mean what you said though. For each (the literal name of a type of iterative loop in coding) means each time you roll, apply a 30% less (*.7) modifier. Nothing about the wording implies it's additive. I think it might be additive, just disagree about that being the literal interpretation of that wording which I found to be very ambiguous.