Stats are pretty limited unless you're able to show a video of what was happening when each was ticked off, but I accept that perhaps our defence wasn't the issue and instead it was our midfield (if our defenders were so busy) or Millwall playing better than I credited them for.
However, if Flint's performance was 10/10 then I'm expecting other defenders to get 12/10 later on this season which makes the whole grading system meaningless.