@bucketbot27 said:

There are several episodes that are long and they are listed as parts 1 and 2. It should be just 1 episode. This is how it is on the DVDs, also imdb.

Fun Run shroud be E01 Dunder Mifflin Infinity should be E02 Launch Party should be E03 Money should be E04 the next episodes should follow the sequence as normal. Goodbye Toby should be E14

Our reference is not the DVD, but the first TV broadcast and the official site indicates that "Fun Run", "Dunder Mifflin Infinity", "Launch Party", "Money" and "Goodbye Toby" are 2 episodes each for a total of 19 episodes in the season.