Google Voice has posted an update to their app which speeds up the call process by assigning a unique phone number to each call made. By assigning a unique phone number to each person called, it eliminates the need to have to route all calls through Google's servers. This new process speeds up the service and makes the service more like a traditional telephone service provider. However, with every advancement there's caveats. It's no secret that T-Mobile customers were able to set up a loophole which drastically reduced their telephone bill. This is how the trick worked: You place one of your "My Faves" numbers as the number from which all outgoing calls would go and the other "My Faves" number would be the phone number from which all incoming calls come from Google Voice. You could thus have unlimited incoming and outgoing calls from Google Voice for the fee associated with the "My Faves" plan.
So if you have been using this loophole, do not update your Google Voice app. You have been warned.