What should my completion score look like based off slide touches?

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So we just migrated a bunch of courses to complete based off of 70% slide touches. We got some interesting data back thus far for our completion scores, like -1, 0 ,80,90, and 100. Is this normal and what do these numbers actually mean? Shouldn't a complete = 100? Or at leas 70 since that's our threashold for complete/incomplete. The completions seem to be working just fine, so it doesn't seem to be a huge issue, but now we're curious.

Thanks in advance!!

Just a heads up we're using scorm 1.2 with articulate storyline.