>So if the temp is low inside the house, the actual pipes can drop way below that temp (50 in this case) and get to freezing.

On top of that, the cabinets installed along those outside walls will further insulate the pipes from the warm inside air, allowing them to get cooler than you might think.

If you need/want to have your house get below 60ish, you might want to consider leaving cabinet doors open to help prevent freezing.