You currently have this:
modified_DR = armor_DR + [10 * min(modified_DT, 0) / 100]

1) I believe the brackets are incorrect, the division by 100 should affect the armor_DR portion as well if you look at how the result
is being used, so it should actually be:
modified_DR = [armor_DR + 10 * min(modified_DT, 0)] / 100

2) In section 2.2, you mention that "Under no circumstances should DR fall below zero or above 100."
This is not represented anywhere in the formulas you have listed.
As such, it would appear that when impact of the 10 * min(modified_DT, 0) is negative and exceeds the armor_DR, you keep the negative value around and thus it increases the resulting damage.
This goes against what you have in Section 2.2, so I'm assuming you're actually not allowing modified_DR to go below 0.
The "above 100" case is not actually possible, so that's not a concern.
But the formula should reflect the minimum of 0 as follows:
modified_DR = max{[armor_DR + 10 * min(modified_DT, 0)] / 100, 0}

Но если armor_DR берется для расчета как 0,3 (вряд ли), то тогда все получится правильно и в последующей формуле

Тестировать буду в ходе прохождения 1,5 Resurrection