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

Boss Reverse Combo also needs some confirmation, as I interpret the readout to be automatic, i.e. every x seconds +1 combo. It doesn't explicitly state +1 Combo per hit, or attack.

Is it even possible to do that? I can't imagine a way to make the game recognize you fighting a boss outside on hit verification. It sounds like +1 per hit to me considering every other mechanic in the game.