First off, is this something they will catch at the interview? 10 hours isn't that much. I have found several mistakes in my logbook over the years, and whereever I am in my logbook, I make an entry and write in "correction", the date of the original entry, and why I had to make the correction (ex. math error), and then put in the proper time whether positive or negative. Never been questioned at an interview, but I'm not sure if they ever even noticed it.