Aggregated Results Slide - Issues When Resuming A Course

I'm hoping someone can help. I'll try to be as detailed as I can. I can share the SL3 file offline, also, but since its for a client, I'd rather not share here publicly. Anyway, the problem...

I have a branching course where you can take one of three "paths", which end up in one of 4 assessments (one of the "paths" has two different assessments). Each of these assessments has its own Results Slide that no one ever sees. I created a blank slide to serve as the Overall Results slide that creates a new variable—"overallscore"— and sets it to the same as whatever the appropriate Result Slide they got. Works great for displaying the proper score, regardless of whatever path they go down.

I had even gotten it to pass to the LMS correctly by creating an Overall Results slide that no one saw behind the scenes. And it works fine so long as you only take one assessment. BUT, during testing, we noticed that if you are on the black overall slide that I created, see your accurate score, then exit the course, go back in and resume, it now ADDS that score several times over, turning a fail to a pass and giving upwards of a 400% overall score! No idea how to fix it, and I'm headed towards full burn of my project hours. Help...?