On an another perspective:
a) If I suppose to correct a paper from another, and he invites me to be a co-author. Will I accept the invitation? (Honestly: no)
b) If another person (B) actively ask to correct my paper, and after that my boss asks me to add B as co-author, will I agree? (Yes. Since this is what the Boss said)
c) If a team member, B, asks to correct the paper of A, I think as a manager even if the work is done by A, but since B helps, will I ask A to add B as co-author? (Honestly: no)
Maybe I have to learn more.