Netbackup Deduplication and Front End Terabyte (FETB)

Hi,

I am hoping for some guidance in the area of Symantec calculating its (Capacity Licensing on FETB - Front End Terabyte) when data is initially deduplicated to disk and then backing up the data to tape after several months.

Query: If we create an SLP (Storage Life Cycle policy) that continually dedupe data from the client machine and then backing up the deduped data from disk to tape after x months, what will be the total FETB (Capacity Licensing)? Will the calculation be based on the initial "FULL" backup of the client or the eventual dedupe amount of data (as the dedupe data over a period of time when cutting over to tape)?

Hypothetical scenario

Client A = 500 GB (Full backup)

              = Deduped data 50 GB on disk (Total after 3 months)

What is the correct calculation when executing nbdeployutil tool? Will the total FETB be 50GB or 500GB?

Any information is much appreciated!

Thanks!!