SSO on Self-Service Portal FortiAuthenticator

I am implementing the FSSO configuration on my FAC 6.5.4 and I also want to implement the FAC Captive Portal to SSO users who have not done so transparently. My question is the following... I have scenarios where I have machines shared with the same Windows user and the turnover of users to access is high, the idea was that each user who connects through the SSO portal would have a timeout of minutes, or if you closed the browser, you would be logged out and would be prompted again if you opened the browser again..., in the FAC configuration there is a timeout but it does not work.

I read that FAC has a Cookie that caches it for 30 days, can I configure this?