The IP address for her home is probably part of a pool of IP addresses assigned to an internet service provider. When you look up the location of the IP address, you find the location of the ISP, not the physical location where the IP address is being used.
Look up your own public IP address and then look up the location associated with the address. Unless you have your own IP address space assigned to you, the location will be for your ISP.
Interesting that it pinpointed a government office. Maybe the ip address was part of a pool that was assigned (as you mention).