Courses are only connected to the LMS on the server during course import. The imsmanifest.xml file and the course metadata xml are fed to the LMS when the course is created. After that, when the course is launched at runtime, the only communication happens through the SCORM JavaScript API. One of the first challenges to making a SCORM conformant system is determining what is "content functionality" and what is "LMS functionality". Calculating a score is almost always the responsibility of the content. If calculating the score requires server side calculations, you might need to look into some alternative solutions to make your content more portable.