I understand the principle of DLU's. Different devices have different cost. Buy enough DLU's and deploy handsets as required until you run out of DLU's (as I understand it).

However, when you buy UCCS for UCM (Software upgrade protection), this appears to be listed as "per user".

Is it right that you buy the licences on a per device basis, yet you buy the software support on a per user basis ? How are the 2 linked ?

For example :

If I buy 400 DLU's to cover 100x 7941's (100x 4DLU's). 20 of those handsets may be in communal areas. So does this mean I buy an 80 user UCSS-UCM (as 80 are on users desks, with a staffing of 80).

Or am I missing something ? I thought initially that you would buy UCSS per DLU.

Any clariffication would be very much appreciated, I cannot find this specific query illustrated in cisco documentation.