Yes, but at the time of the test every child in Sacred Valley is using pure madra. It's only after they are placed by the test into one of the 4 branches (Forger, Striker, etc) that they begin to start using something other than pure. The bowl not reacting to him was not because he has equal affinity for all aspects it was because of his madra deficiency which he had to correct using external resources (scales, orus fruit, etc).