To support extra credit in LTI Advantage, when we (an LTI tool) pass a score to Moodle using the AGS scores service, we set scoreMaximum to 0 and scoreGiven to the user's actual score on the assignment.  Here's an example endpoint and payload:

https://moodledomain/mod/lti/services.php/3/lineitems/2926/lineitem/scores?type_id=3

{"timestamp":"2025-02-11T20:18:54.792800Z","scoreGiven":10,"scoreMaximum":0,"activityProgress":"Completed","gradingProgress":"FullyGraded","userId":"181"} 

Moodle responds to this with a 200 indicating success, but no score appears in the gradebook for the user.  We would expect that a 10 would appear, out of the scoreMaximum of 0, indicating extra credit. 

We are aware that the AGS spec requires scoreMaximum to be positive, but Moodle seems to allow a value of 0.  However, it does not seem to reflect the scoreGiven value in that case.