I have a soldier with a hacking skill of 52. I used the System infiltration ability provided by this mod three times to ensure success, because the reward was enemy protocol.
Apparently System infiltration does not reduce the difficulty of hacking, but temporarily increases the soldier’s skill.
52+20+20+20 - 112.
The enemy protocol increased this value by another 20, so I got a soldier with the rank of sergeant with a hacking skill of 132! And this number has become constant!