

Previously, you would have redeemed a single VPP code through iTunes, then manually tracked how many iOS devices that app resides on, and leaves you "on your honor" to verify that you only use as many copies of the app as you have licenses for. When you un-assign an app through Apple Configurator, it makes it available for use on any other iOS device managed through Apple Configurator - but it does not seem to allow you to go and re-redeem the app through another Apple ID.

What Apple Configurator adds is an extra layer of tracking, allowing you to identify not only which codes are redeemed but which specific iOS device the app resides on. Once redeemed through Apple Configurator, those codes will forever be attached to the Apple ID used to redeem them, just as they would be through iTunes. Just to be clear, I don't believe the Apple Configurator allows you to actually un-redeem VPP codes.
