Should be fairly easy to implement with a mirror grade item set to display a scale [incomplete,complete] and a formula which takes the value from the original item and add 1 to it (or instead of the formula, the offset in the original grade item could be set to 1 such that the actual values would shift from 0/1 to 1/2 which is the scale's range). If hiding the original item in the gradebook does not affect its accessibility on the course, then the original item can be set to hidden and only the mirror grade item will appear in the user grade report. 
Gradebook
SCORM scores in Gradebook
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