It's funny to read about some 9%. Where did you get this information?

For 10 Gorgons, the chance is not 90%, but 1 - 0.9^10 = 65%.
Each Gorgon has its own probability. I don't know how else to explain it; people just don't understand... maybe you should study higher mathematics. Read a few pages of the discussion carefully.

It's also funny why 0.9^
What do I care about your discussions? I'm describing my observations, and I can explain them.
Let's take 70 Gorgons. According to your theory, the chance for one creature will be 14.27%, for two it will be 14.27%, and so on. But what do we see in reality? Let's take 70 Gorgons and attack Azure Dragons. Getting -1 and -2 is practically impossible; -3 and -4, etc., almost always occur. Out of a hundred attacks, -1 or -2 will almost never happen. Therefore, you can't divide it the way it's done in your example.

My explanation is closer to the truth: for every ten, it's 90%. And for each ten to miss 10% or at least 5-6 out of 7 to miss at the same time, in probability theory, this is very rare.

For 10 Gorgons, the chance is not 90%, but 1 - 0.9^10 = 65%

- in reality, let's take 10 Gorgons and calculate. Let's do 10-50-100-200 attacks. There's no 65% there; it's consistently 80% or more.