You are highly mistaken to think that the wear and tear on the house will not increase exponentially with additional children.
I will testify that the wear and tear from one child to two children has increased "wear and tear" by much more than just two. Right now there is one adult caring for two children. Make no mistake, four more children and two babies and the care takers resources to supervise and be certain the children do not destroy things will be far less.
Fun little story. My mother ran a day care and as the oldest child I was suppose to be supervising(rolls eyes). Well one of the more high spirited children jumped from the couch to the macromae table that was hung from the light fixture. An electrical fire started. OH MY. Even though I thought I was being responsible how was I to prevent this from happening? If it were a rental who would pay for the fire department to show up? If the mother sued us then whos insurance covers it? Who pays to fix the carpeting and repaint? Well since you allowed a daycare in your rental maybe it would just be considered normal wear and tear that you should expect?