So do SA add to your spell pool in a manner similar to adding ART or DISC?

IIRC, the formal rule in the book is you can add SA dice to any roll for an action which supports the SA's aim or object. So the SA dice are not added to the Pool, but to the roll made with Pool dice -- you can add any firing SAs to both the casting and the anti-aging roll, after allocating dice from whatever your Sorcery Pool is.

Some people prefer to add any SA dice gained to the Pool, rather than to separate rolls, because adding dice to rolls rather than Pools can effectively double the impact from SA dice (if you have an applicable SA of 5, adding 5 dice to both attack and defense rolls is like getting an extra 10 dice in your Combat Pool). This is sometimes seen as a drawback for combat especially, since there's not as much tactical challenge when you've suddenly got a 10 CP advantage over your opponent. But that's a matter of individual taste.