On the same page where you claim it refers to dice for magic damage (which is never done in all of Revised, as this would make mages INCREDIBLY weak. Max damage is 9 dice of damage at Arete 3 for a targeted Forces blast WITH willpower is insane. Mages would just train in guns, they're a lot safer and more reliable.) there is an example of total scoring that reads
"Example of Total Scoring: A mage scores four successes on a vulgar fire blast. Two successes are used for damage, so it inflicts five levels of aggravated damage (four for the successes, one for a Forces effect, aggravated for fire. One success is used because it is affecting a target other than the mage, and the last success is used to strike an additional target. Two targets are struck, each taking five levels of aggravated damage."
p. 209 Mage: the Ascension (Revised)
(Emphasis mine on relevant text.)
I say that the targeted damage is up to 9 with Forces because the example here is using a success to directly affect a pattern (in other words, to bypass targeting). WIthout this, the fireball would need to be directed at a target with an attack roll (say, Dexterity+Athletics to throw). This roll is just like any other attack and can be dodged if it is noticed but it adds the additional successes as dice of damage like any other attack. (So, not a net benefit over a gun or something.)
The method by which you don't need a success for targeting is used in every example of a magical item dealing damage and is inferred through the rules but left unclear.