Hunter: Three demons appear suddenly and begins to attack the students here.  Asa, you made your Spellcraft check and saw what was happening so you get to act in the surprise round.

Asa: Mass Harm affects up to ten targets so I hit the demons and seven students.

Jason: You don't have to hit the max number of targets, you know.

Asa: I hit the demons, SIX students, and Jason's sorcerer.