Platform Base Complete Edition includes all features. You can install as many NetBackuo master servers, or media servers, and use as many MSDP pools, advanced disk, shared tape, database agents, clients as you like...
...as long as the sum total of the largest of any one single backup of any server does not exceed 100TB.
You can keep as many copies as you like in the back-end, on disk, on tape, replicated etc... e.g. a server with 500GB of disk space, and 300GB of which is used, when you backup to dedupe, and replicate off-site, and duplicate that to tape, then you have three copies of the 300GB backup in the back-end (i.e. you have used a total of 900GB (assuming no dedupe) of back-end capacity - but this all still only counts as 300GB of front-end license usage.
On the second day, if someone create a 1GB file on disk on that server, and then you ran another full backup, and then replicated that and copied that tomtape too - now you would have six copies of stuff, three from yesterday, three from today - but now your notional license usage is 301GB because that is the largest of the recent backups.
On the tird day someone deletes 10GB of files, and then you run another full backup to disk, replicate and delete, then this would create three copies of a 291GB backup image - but your license usage so far is stll 301GB out of your 100TB - because the largest in recent backup of this server was 301GB.