Warrior %/s (KMS You & I + GMS Unleashed)

Different skills have different maximum amounts of monsters they can hit.

Damage increases because more targets are being hit. Each target is being hit for (damage)/(number of targets).

If the damage increases because you're hitting each target and it's accumulative, then why is the damage that adds up different from each other? Shouldn't the damage be the same per each target? so i.e. shouldn't the damage that is being added from target to target be the same?