So there is a difference then…the powers can work differently based on the person.
Dave and Karkat are both knights, so they are both fighters. But Dave uses Time and Karkat uses blood (wonder how that worked)
John and Tavros were for Breath. But John was the Heir and Tavros was a Page. So I am guessing that means John had better mastery of Air powers than Tavros so who knows.
So how will Roxy use her powers then…