the cmi.total_time parameter does not return anything

I am programming a SCORM 2004 product. I can update the session_time, it works. I can set the status (passed, failed, etc...) I also can get the cmi.location time. No problems ! But I don't succeed to get the total time ! (cmi.total_time). I have tested on 2 LMS : - On Ganesha the API.GetValue('cmi.total_time') is an empty string. - On Moodle the API.GetValue('cmi.total_time') is just a "P". However i do have the correct logs with correct session times. Anybody have an idea ? Thank you ! EDIT. I also try on cloud.scorm.com and cmi.total_time returns each time PT0H0M0S. EDIT2. Ooops I deleted Donal's edit.