Am I double charged for minutes when forwarding calls?

In this article:

Perhaps you are asking if your call is completely handed off when forwarding from your NumberBarn number to an outside number. 

The short answer is, no. When your call is forwarded, NumberBarn still hangs on to the call, opening up the possibility that you will be billed for calls both through NumberBarn and the forwarding carrier.

While this may have billing implications for some, we find that, in cases where carriers offer unlimited minutes, this is less of a concern.