Hi, you might like to look at this:

www.eff.org/files/filenode/Charter/033802P.pdf

United Stares Court of Appeals For The Eighth Circuit N0. 03-3802

"Only the ISP, however, in this case Charter Communications, Inc. (Charter), can link a particular IP address with an individual's name and physical address"

Ex's phone # is also a wisconsin number because of a friend there that owns the account.
If that is the case then they are probably sharing an ISP connection as well? That would also give you a Wisconsin address.

Basically, ISP addresses are not reliable as traceability and geolocation were not a part of the internet's initial design.