It is worse than this Daniel.  

Multiplexed is where many servers are on one tape.  It basically single
threads the restores.  They do have a feature like TSM for SAP that uses
multiple tape drives to span the data across.  There TSM and NetBackup are
pretty equal, when it works.

The big deal with incrementals in NetBackup is you have to figure it all
out.  It is not automatic.  At least our folks never figured it out.