add on keys in service agreement document

Hi,

I am deploying f5 ltm on client site for first time. Client has forwarded me service agreement he received from F5. Now that agreement document contains 12 line items for F5-ADD-BIG-ROUTING and 2 line items for LTM-2000S. So I understand, that client has 2 F5 LTM servers and 12 F5-ADD-BIG-ROUTING line items are for 12 add-on keys present in email body needed to be used during license activation.

My question is, do i need to use 6 add on keys for each server during license activation(first 6 for one server and later 6 for another) or all 12 keys for both servers.

Regards, GG