It asks: "How many posts do you own that are marked as 'edited' in the same month as 'now'?" So, you can edit 5 posts in September, 5 posts in October, etc., on any day of month, but you can't edit more than that. It doesn't pay attention to how long it's been since you edited. You could edit 5 posts on Sept 30 and 5 posts on Oct 1, and it wouldn't stop you.

More than once? Pictures of cats? These things I cannot abide.