GS REST API - Release CAL after not required anymore

Hi,

is there any way the free up the TM server CAL through the API once it is not required anymore? If I use the TM server REST API, then a new CAL is consumed, but I haven't found a solution to release the CAL once it is not required anymore. It is released only after a timeout. 

In swagger I have found this action: "/authentication/api/1.0/login/signout", but it doesn't seem to release the TM CAL. The GS web seems to call "/authentication/api/token/signout", but it does not do the trick either, if I call it. I call them on groupShareKit like this:

gsClient.Connection.Post(new Uri("/authentication/api/1.0/login/signout", UriKind.Relative))

Is this possible at all? 

thanks,

Tamas