Perhaps this is happening to you. Seems like GV is looking at the IP of the GV call.
See this thread:
http://www.obitalk.com/forum/index.php?topic=1393.msg8785#msg8785I've read that Google Voice charges 1 cent/minute for calls overseas to/from the U.S. even if the user has a U.S. GV number. Is this true? Seems the only way they would know where calls are originated or terminated is by IP address. If it is true, is there a way that a friend overseas with an OBi 100 can call my OBi 100 in the U.S. via an OBi to OBi call, get my auto attendant and then call out to the U.S. via my OBi and thus avoid the 1 cent/minute charge?
Don't forget that you can call each other using the OBi number as well. You could put each other in the "circle of trust" and use the local tel servcies of each OBi.