Buying a house is like attending a signature party. Somebody comes in with a big stack of papers, and you just start signing. There is not human way to know what each of those documents actually say, and you absolutely trust the settlement officer. If not, you read lawyerese for such things as "yes, I'll pay the mortgage and you can come after me if I don't." Most of the paper is "instruments" that are well defined and not changeable.
So anyway, we have a new house. Principal payment is about +$100 over the last principal payment, so the house won't cost very much more per month. However, living now in Rockville proper will cost a bit more in taxes. All in all, this will still be cheaper than private school for Hers Truly.