by AL Rachels.
This is something I learned from helping with QA testing last year. Both the rubric and marking guide will let you setup to use decimal points, but for your grades to make sense, you DO need to have a zero level defined for each criterion.
Just to make sure, I just double checked and this works in my current Moodle 2.6.2+ and Moodle 2.7rc2 sites.