Apple Configurator 1.4 losing app codes when updating apps

I recently upgraded to Apple Configurator 1.4 from the preceding version. Since upgrading I imported updated versions of existing free and paid apps from iTunes. After importing the paid apps the app codes count in the Licences column disappeared and was replaced by "Free". Quitting and reopening Configurator made no difference. Apple Configurator appears to have converted the app to Free in its database and lost access to the VPP app codes.

To recover, I restored the backup database created when Apple Configurator 1.4 is first installed and does its migration. This restored the app codes and count of available codes for the paid apps.

I then tested with a single app - Garageband. The database had version 1.4 of Garageband and 1 remaining app code available out of 50 listed that had been imported to the previous version of Configurator. When I imported into Configurator from iTunes the app Garageband 1.4.1, the import reported as successful but the count of 1 disappeared and was replaced by "Free".

I was again able to restore the database to return the codes.

Please advise what I can do to resolve this issue.