Gradebook

Still setting up Moodle and playing around, I created a scale for grading offline tasks. Of course my boss thinks I should use other words in describing the level of performance, fine I'll go in and change the words. AHHHH!!! Moodle won't let me edit a scale once it's used. I've gone in and changed any activities that used the scale to another scale and any grades I gave with the scale were updated using another scale but still all I can do is go in and edit the name and description of the scale. Is there any other thing that could be locking me out from editing the scales of a scale? Moodle says the scale is still in use, is there any way to find out where it thinks it's still in use?