Why does Fell Stinger raise Mega Beedrill's Attack by at least 3 stages?

Question

According to Pokemon Database, if Fell Stinger KOs a Pokemon, the user's Attack is raised by 2 stages.
But for Mega Beedrill, it says "Beedrill's Attack rose drastically!", so the Attack is raised by 3 stages at least.
Why does this happen?

Comments

It's because the Pokemon Database page is outdated.

Answer 1

Fell Stinger raises Attack by 3 stages in gen 7.