The ATA (box provided by VoIPo) is capable of having a tailored dial plan to reflect your local calling area. Some VoIP providers will tell you how, or help you, or do the changes. But it costs them time to do so, then keep it up as area codes and exchanges change. Best if you are able to alter it yourself as need be - essentially you use a password to access your ATA device and change certain digit string settings per a specific arcane syntax.

But not all VoIP providers allow subscribers to do so.