These are very amusing side stories or "extras" that were published in the manga anthologies, and then included in the DVD release. Presently, they are being aired as special episodes "12.5" and "18.5" of the anime on Crunchyroll. But if you are just watching the numeric episodes, you might miss these, which are given a special heading to indicate that they are not part of the ongoing story. I missed them at first, and only saw them when I went back to look at the list of episodes. I'm really happy to see the fashion episode. Not only is it one of the funniest bitsin the manga, but it really adds some depth to the three characters involved.

I suppose MAL put these in a separate entry because it wasn't part of the original TV series, but in my mind it is all one anime, and would be more appropriately included in a single entry for the first 24 episodes of the show.