Okay, SCORM only defines the way the grading information should pass between the LMS (dotLRN) and the SCO's (learning objects). For grading itself they direct to the IMS standards.
The latest SCORM definition can be found at http://www.adlnet.org/index.cfm?fuseaction=rcdetails&libid=496&cfid=362887&cftoken=94304883 but be warned. It is HUGE :).