Automated updates to multiple contacts


Good morning!

I have a sheet that I am working on for voting on tool enhancement request. I currently have the sheet set up to request voting on 6 categories for a purposed update for our tool. The issue im running into is the update request is being sent to multiple contacts (for test purposes we are using 6 contacts), when the updates are made and sent back it seems like the first persons update is being overwritten by the next person. I can go into the cell history and see all the previous updates, but I am hoping there's a way to add all the ratings together to give me an overall score? Any help would be greatly appreciated.