I don't understand how you present the numbers.
Skill 120% -> 53% to resist, 70% due to BB=4
Makes the full resist to 73% with BB=4, it should be 60% (+13%)
"Skill 120%" = I suppose a skill that has 120% chances to hit?
"-> 53% to resist" = no fucking idea.
"70% due to BB=4" = no fucking idea.
etcetera.
What's the formula you are using to determine resist?