Currently they are able to willing tap into their magic any time and have decent control on direction and usage if needed for combat/other purposes. However they lack the ability to hit their target all the time and will have a slight hit/miss ratio of 1 out of every 3 attacks. Part of learning the basics is also control, arcanite used, aim and stuff like that. Each time their power increases, they have to re-establish those basics again to adjust to the new power. 

I would say what you listed is possible and reasonable for your blood.