My group sided with the key word being "roll". Thus, if you attacked someone with fire and intent to kill (given 5 conviction, 5 discipline), you'd end up with a base of 5 shifts for power, with essentially a 6 base for discipline to control it, as well as a 6 base for discipline to aim it. It gives you less points than refinement (because you'd get two +1s), but is possibly broad enough to justify it.