I have a 16 cha lvl3 lock with only 2 spells per day. Lvl 1 and 2 combined. Shadow heart is fine with 4 seperate lvl 1 casts and 2 lvl 2 casts.
I made my astairion an arcane trickster gave him intellect ciclet to set int to 18. He still has 2 casts.
Am i missing something?