702.175. Offspring

Offspring represents two abilities. “Offspring [cost]” means “You may pay an additional [cost] as you cast this spell” and “When this permanent enters, if its offspring cost was paid, create a token that’s a copy of it, except it’s 1/1.”

If a spell has multiple instances of offspring, each is paid separately and triggers based on the payments made for it, not any other instances of offspring.