You probably noticed that sometimes you have mana increase in your available magic school when you gain the level and sometimis you don't. I had nice theory about it - with Rules and exception from the rules all worked out ( it deals with either or not you have unknown high level spell in your school), but few levels ago my theory went down to drain. So now I am in the state of confusion. I know that if mana increase it increses by the ammount equal to the Spirituality of your character, and I know that this process is not random, but this is it. Any ideas?