Abyssal Wisp's Trait isn't working

My Abyssal Wisp casts Unanswered Prayers wich resulted in 5 Times casting the spell.

Unanswered Prayers is normaly cast 4 times, Abyssal Wisp’s Trait let him cast spells 3 additional times. So he should cast it 4 times, wich means 4x4=16 times Unanswered Prayers.

Or am I wrong?