Spell supplies in conflicts

Conflict spells like Wizard’s Aegis don’t require a separate spell-casting roll. When you use spell supplies with these spells, do you get the +1D for each relevant action in the conflict (i.e., each time you use Wizard’s Aegis to defend)?

p44 Spells in Conflicts
"Some spells, like Eldritch Darts, give magicians and rangers the ability to use Arcanist in place of other skills for particular types of actions in conflicts. These spells are cast during the conflict on the caster’s action." (My italics)

I read this as each time a caster rolls for an action in a conflict using a spell like Eldritch Darts or Wizard Aegis, it is a separate casting of the spell.

So I’d say using supplies would give the caster +1D to only one roll in a conflict. And if the caster acted again in the conflict using that spell, they’d need to spend another supply to get +1D again for their action roll.

Oli’s got it. One roll.