I would think the issue might be with insurance. I'd look into it to see what the rules are if I were in your shoes. While no doubt you can handle that number, it may be outside the legal limit of 5. This, in turn, will negate your insurance which is a pretty gigantic problem if something happens to any of the kids in your care when over ratio. I would think it might behoove you to look into it further. My inclination is that your grandchild would have to count in your numbers....but I've been wrong before