An outbound call would not have an incoming leg since it's going from our network to the outbound destination, it's it's only billed the outbound.

An incoming TF call for example could have something like this:

Incoming Leg to VOIPo

Outgoing Leg from VOIPo To Final Destination

An outgoing call across town would only have this:

Outgoing Leg from VOIPo

Think about what the call has to do to get to/from VOIPo.