How to save individual answers in a question

Hello!!!
I am creating a time allocation survey for my team, which will have a quarterly send out to gather how they spent their time on average a week, according to our companies 7 accountabilities.
At the end of the survey, I have a verification question asking "you stated you work XXX hours a week, is this accurate? If not, please go back and adjust as needed."
THE ISSUE is that when you go back in the survey (have the back buttons enables and autosave enables), the numbers you entered into the "Constant Sum" questions is erased. I know if it was me taking the survey, I would stop there and give up instantly.
Anyone know where the issue might be? I know it is possible, because I am basing this survey off of another one that has similar questions, and they have it so they save individual responses (use a matrix question though, not constant sum).