so I just realized that I had an error in my logbook and would like to pick your brains about how to handle this. While totaling one page I noticed that the multiengine and the single engine time that I had didn't add up to match the total flight column.

Total single engine - 389.7
Total multi - 10.9
Total flight time - 424.3

As you can see this is a huge difference (at least for as few hours as I have) of nearly 20 hours in my favor. Looking back indicates that this is a number of errors over the last few years. How should I go about fixing this error for job interviews in the future?

The options as I see it are to either go back and add up all columns again to see which one is in error, or to rewrite the entire log book from the ground up (issues there is I loose my instructors signatures for allmy flight training). I want to get this fixed the proper way, but don't know how to fix it.

Any suggestions?
Thanks for reading all this!