The Strongest Hero with Negative Destructive Power - Chapter 17

Honestly this story is all over the place how can he absorb mana but then some dude at “30%” shooting two mana bolts he can’t absorb half of 30% of a students mana but he fucked up the A rank damage dealer like he was a little kid. They said the A rank bully was only in lower due to poor coordination. It’s really really confusing the power scaling of this story, the main character is op af and then turns to complete dogshit the next chapter. I don’t like systems with power and skill levels but this is why so many stories use it, because we have shit like this where the main character treats a A ranker like a little baby, then 5 chapters later the main character is getting his add handed to him by a guy at “30%” wtf is that guy’s ranking? SSS?