It's not necessarily their main location that is the IP location. It's whatever is registered as the location for the site to which your ISP connects you. In my case, it's a small town where their central station is located about 30 miles south of my actual location. I don't know how you are using your iPad in a store, but if the GPS cannot receive a signal, it will use the IP location process. If there is a WiFi in the store, and you connect, the location will be the location of the STORE's provider, which could be anywhere. And if the IP used the the IP from your cellular provider, that again could be almost anywhere on Earth, literally. It's not really strange, it's just how unreliable IP location is. I have a VPN service that I occasionally use to connect overseas. When I do that, my visible IP is on the far end. If I connect to someplace that uses IP Location, like speedtest.net, they think I'm actually IN those foreign countries.