Based on spell or spell slot?
Just curious if an 11th level heightened spell would have a -10% chance to disbelieve it :). --Aarnott (talk) 16:18, 20 October 2016 (UTC)
Actually... On second glance it looks like the spell level. So no negative percent chances of things happening. --Aarnott (talk) 16:20, 20 October 2016 (UTC)