It was extended because they couldn't find a female lead for their up coming project Replacement something, I forgot the title. But they found one. So there's actually 24 episodes.
Episode 20 was dreadful to watch. It doesn't mean I dislike it lol it's time things are slowing down for us to dedicate our hatred on Vivian at full blast. Oh I loathe her so much!!! How pathetic that she pretends to be blind!!! Who knew that 2 minutes of XK and SJ can make me go googoogaga. She needs to answer him in a corny way just so that I will be a happy camper. Because episode 21 seems like it will not bring me any happiness. Vivian is CRAZY!!! She needs to go to the mental institution!