If Gazimon and Commandramon (both virus Digimon) were giving off 10 damage against this enemy virus Digimon, let's say for demonstration purposes that Bakumon's attack did 20 damage. Still significantly more damage (2x) than what Gazimon or Commandramon was doing, but not a huge dent to a Digimon that is Champion and has say . . . 300HP.
Commandramon was able to use a full strength Champion level attack because he was granted a card that specifically allows for this to happen. Without the card, he would never have been able to use the ability. Even if he shared an attack with an Ultimate level Digimon, it would not be as powerful because Rookie level Digimon can't pack as big a punch.
I don't know if that helped at all, but that's what I'm gathering/envisioning.