There is an error using SCORM 1.3 when you are saving "cmi.session" time in scorm. The error is focused in file "mod/scorm/datamodels/scorm_13.js.php", at function AddTime, around line 1020.

When you are splitting the time format using a regular expresion, you are taking the wrong position of the array, and you are storing the minute value of the session in the hour and minute position of the database:

(Original line)
            var hours = parseInt(firstarray[10],10)+parseInt(secondarray[10],10)+change; //Hours

(Corrected line)
            var hours = parseInt(firstarray[9],10)+parseInt(secondarray[9],10)+change; //Hours