Not very big deal, but with two barrel APU spells I was using so far, stock version directly from vendor dont show damage numbers, mobs and user are damaged normally.
Energy barrel:
http://i.imgur.com/ggyARmD.jpg
Fire barrel:
http://i.imgur.com/FA3gRfQ.jpg
Here is energy barrel constructed by myself with psi enhancement mod and its working like it should:
http://i.imgur.com/SdtCKKH.jpg
Multi energy bolt is not affected.