One of my players wants to make a cleric15/paladin5 in the group and he says that the number of turnings per day of cleric stacks with the number of turnings of the paladin. So, he would have 3 + char turnings for the cleric and 3 + char turnings for the paladin. I said to him that the number of turnings doesn't stack, the only thing that stack are the levels to determinate the the turning level of the cleric(18 in this case, 15 for cleric and 3 for paladin). Am i wrong? Or it's correct?