Named cals are user specific. So the admin must have assigned these users a named cal. So they are not unused. if you go in Setup --> Licences --> QVserver --> Assigned cals you should be able to verify that.
So it is not uncommon that they used both, if the used two different ways to open an application : IE plugin and Ajax for example.
Thanks for your reply .. In this case i'm the Admin and i'm sure that I have not assigned those users Named Cals and
i'm in a impression that we have 5 Named cals unused but we recently found that all the named cals were used and
i'm just figuring out how this may have happened,I'm assuming that some user from Document Cals might have
occupied Named Cals . Is it actually possible ?
Has "Allow dynamic CAL assignment" been enabled in your QVS? See QMC->System->Licenses->QlikView Server->Client Access Licenses (CALs)->General, and the corresponding tab for Document CALs attached to your document.
BTW which version of QVS are you running (please be specific, there are quirte a few different releases of QV 11.xx)?