Need to understand how "NBU OpCenter Analytics Agent" license works

Since the NBU license "NBU OpCenter Analytics Agent" is per client based. Need to know how it works.

1.  we have around 500 clients. Can we buy a key for ten "NBU OpCenter Analytics Agent" and try them out?

2. if we buy 10 clients for "NBU OpCenter Analytics Agent". will it work for only 10 dedciatd clients? for exmaple, if i need a backup report, will i only be able to generate a report with 10 client older than 60 days?

3. does the "NBU OpCenter Analytics Agent" currently work for "search and hold" function?

thanks in advance.