Norton Internet Security - NIS - licences

hello to all,

been a Norton Antivirus (NAV) and then Norton Internet Security (NIS) for a very long time.

when i upgraded from NAV to to NIS, i initially acquired a '5 user' licence.

as my wife's business grew, i added a '3-user' licence.

i needed the second license as that was the only way NIS was offered.

here's the issue / question:

i just renewed my '5-user' NIS lic for another year - auto renewal.

i logged on to my Norton account to check the lic status and discovered the following:

the '5-user'  lic has changed to a '10-seat' lic.  not sure when this occurred.

what does this mean ??  can this lic now support 10 different PC's ??

if yes, can i now add my '3-user' lic PC's to the '10-seat' lic and remove the '3-user' lic ??

this has potential to save money and more important, the effort to maintain 2 separate NIS lics on multiple PC's.

if not, then what does '10-seat' really mean ??

also, i received no notice that this would be changing.

any help would be appreciated.

Thanks  

Jim S.