Yes, it is directly related to pixie output, default of -v 3 when -d is used will only ouptut:
whereas -v 4 will not only show the actual hashes recovered, but also echo the pixiewps command ran.
[P] ENonce received.
[P] PKE received.
[P] RNonce received.
[P] PKR received.
I chose to do this to reduce screen clutter unless extra verbosity is desired. Most "users" don't care _how_ it works, only _that_ it works.
Further work is planned with this: code cleanup, extra options, hash recording, integration with other projects, etc... ;-)