Entitlement Management Licencing

I understand the licencing requirements for using access packages in entitlement management is that you have as many P2 licences as people that can request access package. My question is that if I have 1000 P2 licences in my directory of 2000 users, do the users I make an access package available to need to have the P2 licence assigned to them, or is it simply the case that I need to have equal to or more P2 licences than people that can request access packages. 

I'd like to create an access package and make it available to 200 users, but not all of these 200 users are assigned a P2 licence from our pool of 1000.