Guys there's a misconception here. When a bonus is applied, it affects that area of the pitch, not individual player abilities/skills.

So, let's say you have +8% defense. This means that during the game, your defense stats will be +8% higher than the would've been without it. Players' stats are exactly the same, but the global stats of their influence area goes up.

Same happens when you watch a live match, your team possession goes up by +8%, but it doesn't individually modify your players' stats/skills.