I've noticed this before, but it especially bothers me now that I've taken over an abandoned show. We have 1.5 episodes out of 25 subbed, yet on the thumbnails and front page of the show, it says "100%." This number kept updating as we subbed the first episode.
This is just misleading. I think the total should account for the percentage across all episodes. So ours would actually say 5%. That way, people don't come across the thumbnail and think the show's completely subbed only to be disappointed.