Short and Simple: No
It does not ncrease any chance for anything, neither buff, nor debuff, it only decides, if the debuff effect will be active or resisted, once it has been determined by the chances that it will even hit the enemy.
I recently saw a video on YouTube by "Hell Hades." He stated that a skill percentage is the probability of CASTING attempts of a skill, not the probability of success of the skill. Or, in other words, if an A2 with a skill probability of 35% is activated, out of 100 A2 activations the skill would be attempted 35% of the time.
My idea is that the skill is attempted 100% of the time, and 35% of the time, all things being equal, will be successful. Which is correct?