Don't worry. You have your receipt to verify the times and simply made a data entry mistake. It's fixable.
I always get a little "sensitive" when QC emails show up. There are 2 questions from them that I hate:
1. Why was there a delay in either ordering, getting to the window or receiving my food? How the heck should I know? Unless it's obvious (like a fire in the kitchen), I have no clue why tasks take longer than 1 minute to achieve.
2. What were you wearing? This has only happened when the report was not perfect and is a pathetic attempt at finding the shopper. What I was wearing while performing the shop will not make the reported issue go away.
I've only had 1 shop rejected from them after I naively answered the "what were you wearing?" question, which was quickly followed by "you've been identified by an employee". Timing issues, with back-up proof like receipts, have always been resolved and I have been paid.
Try not to sweat it too much. I have a good feeling that your shops will be accepted with a little note from MF to be more careful next time. Good luck!