There is a bug in the Licensed Sessions by Last Access Date view and it does not filter out expired licensed sessions which has been fix in the upcoming 7.5 release.
As far as multiple licenses being consumed when incidents are opened from email.
You should ensure that the "c.Support Application URL" setting in Global Configuration, which is used for notifications, has the same host name as the URL your reps are using to access the c.Support Desktop.
There is also a "Application Url Redirect" workaround for the following example and our support department can assist you with implementing it.
Example
Lets say your c.Support web server is named "cSupportServer" and is in the "gwi" domain.
Cookies are used to track a reps licensed session and they are tied to the host part of the address.
http://cSupportServer.gwi.com/rep and http://cSupportServer/rep resolve to the same web site but have different host names and will get separate cookies.
If you navigate to http://cSupportServer/rep and log in you will consume one licensed session.
If you then open a new window, navigate to http://cSupportServer.gwi.com/rep, and log in you will consume a second licensed session.
Dan Green
Sr. Software Architect
GWI Software